diff --git a/README.md b/README.md
index 3ea4bbf..3242edc 100644
--- a/README.md
+++ b/README.md
@@ -17,13 +17,13 @@ tag. They depend on each other by version, so install the ones you use
 **and the packages they depend on** from the same tag:
 
 ```bash
-pip install "lambdafeedback-slr-parsing @ git+https://github.com/lambda-feedback/lambda-feedback-packages.git@v0.3.0-rc.3#subdirectory=slr_parsing"
-pip install "lambdafeedback-criteria @ git+https://github.com/lambda-feedback/lambda-feedback-packages.git@v0.3.0-rc.3#subdirectory=criteria"
-pip install "lambdafeedback-expression-parsing @ git+https://github.com/lambda-feedback/lambda-feedback-packages.git@v0.3.0-rc.3#subdirectory=expression_parsing"
-pip install "lambdafeedback-units @ git+https://github.com/lambda-feedback/lambda-feedback-packages.git@v0.3.0-rc.3#subdirectory=units"
+pip install "lambdafeedback-slr-parsing @ git+https://github.com/lambda-feedback/lambda-feedback-packages.git@v0.3.0-rc.4#subdirectory=slr_parsing"
+pip install "lambdafeedback-criteria @ git+https://github.com/lambda-feedback/lambda-feedback-packages.git@v0.3.0-rc.4#subdirectory=criteria"
+pip install "lambdafeedback-expression-parsing @ git+https://github.com/lambda-feedback/lambda-feedback-packages.git@v0.3.0-rc.4#subdirectory=expression_parsing"
+pip install "lambdafeedback-physical-quantities @ git+https://github.com/lambda-feedback/lambda-feedback-packages.git@v0.3.0-rc.4#subdirectory=physical_quantities"
 ```
 
-With Poetry: `lambdafeedback-units = { git = "https://github.com/lambda-feedback/lambda-feedback-packages.git", tag = "v0.3.0-rc.3", subdirectory = "units" }`, and likewise for each package.
+With Poetry: `lambdafeedback-physical-quantities = { git = "https://github.com/lambda-feedback/lambda-feedback-packages.git", tag = "v0.3.0-rc.4", subdirectory = "physical_quantities" }`, and likewise for each package.
 
 ## Packages
 
@@ -32,7 +32,7 @@ With Poetry: `lambdafeedback-units = { git = "https://github.com/lambda-feedback
 | `slr_parsing` | `lambdafeedback-slr-parsing` | `lambdafeedback.slr_parsing` | Generic SLR(1) parser engine | — |
 | `criteria` | `lambdafeedback-criteria` | `lambdafeedback.criteria` | Criteria DSL parser and evaluation graph | `slr_parsing` |
 | `expression_parsing` | `lambdafeedback-expression-parsing` | `lambdafeedback.expression_parsing` | Safe SymPy parsing, preprocessing and LaTeX input/output | `slr_parsing`, `sympy`, `latex2sympy2_extended` |
-| `units` | `lambdafeedback-units` | `lambdafeedback.units` | Unit-system data, physical-quantity parsing and dimensional analysis | `slr_parsing`, `expression_parsing`, `sympy` |
+| `physical_quantities` | `lambdafeedback-physical-quantities` | `lambdafeedback.physical_quantities` | Unit-system data, physical-quantity parsing and dimensional analysis | `slr_parsing`, `expression_parsing`, `sympy` |
 
 ```python
 from lambdafeedback.expression_parsing import (
@@ -41,7 +41,7 @@ from lambdafeedback.expression_parsing import (
     parse_expression,
     preprocess_expression,
 )
-from lambdafeedback.units import QuantityParams, parse_quantity
+from lambdafeedback.physical_quantities import QuantityParams, parse_quantity
 
 params = ExpressionParams.from_dict(evaluation_params)  # JSON parameters → typed
 pre = preprocess_expression(response, params, name="response")  # aliases, brackets, |x|
@@ -54,7 +54,7 @@ quantity = parse_quantity("9.81 m/s^2", QuantityParams.from_dict(evaluation_para
 from [toolkit-python](https://github.com/lambda-feedback/toolkit-python), with
 `CriteriaGraph.export_feedback` for criteria feedback.
 
-Each package uses a `src/` layout: `units/src/lambdafeedback/units/`.
+Each package uses a `src/` layout: `physical_quantities/src/lambdafeedback/physical_quantities/`.
 There is deliberately no `lambdafeedback/__init__.py`; the namespace is
 [PEP 420](https://peps.python.org/pep-0420/), so the separately installed
 packages merge under one import root.
@@ -69,7 +69,7 @@ that installs every package in develop mode, plus the tooling, into one venv:
 ```bash
 poetry install                      # creates the venv with all packages + dev tools
 poetry run scripts/test.sh -q       # every package's tests (one pytest process each)
-poetry run pytest units/tests       # a single package
+poetry run pytest physical_quantities/tests  # a single package
 poetry run ruff check . && poetry run ruff format --check .
 poetry run mypy
 poetry run python tools/parity/check.py   # diff behaviour against the v0.1 baseline
@@ -121,7 +121,7 @@ attached to a GitHub Release (marked as a pre-release for pre-release tags).
 ## Logging
 
 The packages log at DEBUG only, through loggers named after their modules
-(`lambdafeedback.expression_parsing.preprocessing`, `lambdafeedback.units.quantity`, ...):
+(`lambdafeedback.expression_parsing.preprocessing`, `lambdafeedback.physical_quantities.quantity`, ...):
 how a response was preprocessed and read, how a quantity was split into value
 and unit, which evaluations a criteria graph ran. Failures are exceptions, not
 log records. To see them:
diff --git a/criteria/CHANGELOG.md b/criteria/CHANGELOG.md
index 4cdd184..3884b17 100644
--- a/criteria/CHANGELOG.md
+++ b/criteria/CHANGELOG.md
@@ -1,6 +1,6 @@
 # Changelog: lambdafeedback-criteria
 
-## 0.3.0 (unreleased; pre-release 0.3.0rc3, tag v0.3.0-rc.3)
+## 0.3.0 (unreleased; pre-release 0.3.0rc4, tag v0.3.0-rc.4)
 
 The first public release, after the extraction refactor. The import path is now `lambdafeedback.criteria` (was `criteria`). There was no 0.2.0 release: all four `lambdafeedback-*` packages share one version, and the first release is 0.3.0. Supports Python 3.12 to 3.14 (3.11 is not supported); `__version__` gives the installed version.
 
diff --git a/criteria/README.md b/criteria/README.md
index a809222..e8e4acd 100644
--- a/criteria/README.md
+++ b/criteria/README.md
@@ -14,7 +14,7 @@ evaluation function.
 From git (not on PyPI yet):
 
 ```bash
-pip install "lambdafeedback-criteria @ git+https://github.com/lambda-feedback/lambda-feedback-packages.git@v0.3.0-rc.3#subdirectory=criteria"
+pip install "lambdafeedback-criteria @ git+https://github.com/lambda-feedback/lambda-feedback-packages.git@v0.3.0-rc.4#subdirectory=criteria"
 ```
 
 Install the packages it depends on (`slr_parsing`) from the same tag; see the [repository README](../README.md#install).
diff --git a/criteria/pyproject.toml b/criteria/pyproject.toml
index a4f4e2c..719ecf6 100644
--- a/criteria/pyproject.toml
+++ b/criteria/pyproject.toml
@@ -4,7 +4,7 @@ build-backend = "poetry.core.masonry.api"
 
 [project]
 name = "lambdafeedback-criteria"
-version = "0.3.0rc3"
+version = "0.3.0rc4"
 description = "Criteria parser and criteria graphs that turn evaluations into feedback, for Lambda Feedback evaluation functions."
 readme = "README.md"
 license = "MIT"
@@ -25,7 +25,7 @@ classifiers = [
 ]
 requires-python = ">=3.12"
 dependencies = [
-    "lambdafeedback-slr-parsing (>=0.3.0rc3,<0.4.0)",
+    "lambdafeedback-slr-parsing (>=0.3.0rc4,<0.4.0)",
 ]
 
 [project.urls]
diff --git a/expression_parsing/CHANGELOG.md b/expression_parsing/CHANGELOG.md
index 9e94b36..a9cf8fc 100644
--- a/expression_parsing/CHANGELOG.md
+++ b/expression_parsing/CHANGELOG.md
@@ -1,6 +1,6 @@
 # Changelog: lambdafeedback-expression-parsing
 
-## 0.3.0 (unreleased; pre-release 0.3.0rc3, tag v0.3.0-rc.3)
+## 0.3.0 (unreleased; pre-release 0.3.0rc4, tag v0.3.0-rc.4)
 
 The first public release. Further tidy-up after the 0.2.0 extraction: previewing a response and mapping failures to learner-facing feedback text are app-layer concerns, so they move out of this package. `__version__` gives the installed version.
 
@@ -59,9 +59,9 @@ The first public release. Further tidy-up after the 0.2.0 extraction: previewing
 - (since 0.3.0rc1) `parse_latex` leaves division between numbers unevaluated, as the lambda-feedback fork did: `\frac{10}{2}`, `10/2` and `10 \div 2` give `10/2`, and `\frac{3}{6}` gives `3/6`. In rc1 latex2sympy2_extended divided two integers as a `Rational` (`5` and `1/2`), so a "written as" criterion couldn't tell `\frac{3}{6}` from `\frac{1}{2}`. `2\frac{1}{2}` is the product `2*1/2` again (rc1 read it as the mixed number `5/2`).
 - `parse_expression` leaves every SymPy function unevaluated, not only the ones SymPy's own `evaluate=False` covers (trigonometric, `exp`, `log`, ...). `factorial`, `binomial` and the number-theory functions computed while parsing: `10000000!` took minutes, and `100000!` gave an integer too long to print. As a result `5!` now parses as `factorial(5)`, not `120`, like `sin(0)` stays `sin(0)`; with `simplify` they are still computed. `parse_latex` likewise leaves `\binom` unevaluated (`\binom{5}{2}` gives `binomial(5, 2)`, not `10`): latex2sympy2_extended computed it, and `\binom{100000000}{50000000}` didn't finish. Operator classes called by name (`Pow`, `Add`, `Eq`, ...) are left unevaluated too: `Pow(9,Pow(9,9))` never finished, in every mode.
 - **One LaTeX differential broke every later LaTeX parse in the process.** latex2sympy2 (and the lambda-feedback fork) overwrote a module-level variable when parsing `\mathrm{d}x`, after which every `parse_latex` call failed with "argument of type 'Symbol' is not iterable"; in a warm evaluation-function container, one learner's answer broke LaTeX for every later request. latex2sympy2_extended keeps no state between calls. (Upstream issue OrangeX4/latex2sympy#4, closed unfixed.)
-- `substitute` scales with the input's length. It tried every substitution at every position, and a `FunctionName` copied the rest of the input on each check, so a long response with many substitutions was slow: 100000 characters with the units package's ~1000 reserved names took over 10 s. Substitutions are now indexed by their first character (keeping their order, so results are unchanged).
+- `substitute` scales with the input's length. It tried every substitution at every position, and a `FunctionName` copied the rest of the input on each check, so a long response with many substitutions was slow: 100000 characters with the physical quantities package's ~1000 reserved names took over 10 s. Substitutions are now indexed by their first character (keeping their order, so results are unchanged).
 - `is_complex_number_on_exponential_form` took exponential time on inputs like `2*exp(` followed by a run of digits (26 digits took over 10 s), which a learner's response could trigger through "written as" criteria. `NUMBER_REGEX` and `NONNEGATIVE_NUMBER_REGEX` could match an empty string after a digit, and the check repeated them; they now never match empty (they accept the same numbers), and the complex-form checks match each number atomically. `is_complex_number_on_cartesian_form` no longer accepts an empty string or a lone `+`, and both checks no longer accept numbers run together (`5E7e7`, `exp04I`). `generate_arbitrary_number_pattern_matcher` matches each number atomically too: a pattern whose numbers are separated only by spaces (`1 2 3`) took polynomial time on a long run of digits (1000 digits: over 8 s), and matched a single number (`3`) through the empty-match bug.
-- `ExpressionParams` (and so `SympyParsingConfig`, and subclasses such as `lambdafeedback.units.QuantityParams`) can be pickled and deep-copied. `symbols` is a read-only `MappingProxyType`, which pickle can't handle; it is stored as a `dict` and wrapped again on unpickling, without validating again.
+- `ExpressionParams` (and so `SympyParsingConfig`, and subclasses such as `lambdafeedback.physical_quantities.QuantityParams`) can be pickled and deep-copied. `symbols` is a read-only `MappingProxyType`, which pickle can't handle; it is stored as a `dict` and wrapped again on unpickling, without validating again.
 - A symbol code that merely contains `lambda` (e.g. `lambda_1`) keeps its name. Every substitution's replacement had `lambda` rewritten to `lamda`, so `lambda_1` became `lamda_1`, which was then split as `lamda*_1` and lost its LaTeX.
 - A task symbol whose code is a Python keyword (`in` for inches, `del`, `as`, ...) parses as that symbol, keeping its LaTeX and assumptions; it used to raise (or, for `as`, become `a*s`).
 - `sympy_to_latex` prints symbols that have assumptions (from `symbol_assumptions`) with the task's LaTeX. The printer matched symbols by equality, and `Symbol('x', positive=True)` is not `Symbol('x')`.
diff --git a/expression_parsing/README.md b/expression_parsing/README.md
index 6d4b656..09e61ce 100644
--- a/expression_parsing/README.md
+++ b/expression_parsing/README.md
@@ -11,7 +11,7 @@ functions such as compareExpressions.
 From git (not on PyPI yet):
 
 ```bash
-pip install "lambdafeedback-expression-parsing @ git+https://github.com/lambda-feedback/lambda-feedback-packages.git@v0.3.0-rc.3#subdirectory=expression_parsing"
+pip install "lambdafeedback-expression-parsing @ git+https://github.com/lambda-feedback/lambda-feedback-packages.git@v0.3.0-rc.4#subdirectory=expression_parsing"
 ```
 
 Install the packages it depends on (`slr_parsing`) from the same tag; see the [repository README](../README.md#install).
diff --git a/expression_parsing/pyproject.toml b/expression_parsing/pyproject.toml
index d0a99ef..908c5b6 100644
--- a/expression_parsing/pyproject.toml
+++ b/expression_parsing/pyproject.toml
@@ -5,7 +5,7 @@ build-backend = "poetry.core.masonry.api"
 
 [project]
 name = "lambdafeedback-expression-parsing"
-version = "0.3.0rc3"
+version = "0.3.0rc4"
 description = "Safe SymPy parsing and preprocessing of learner-written mathematical expressions, for Lambda Feedback evaluation functions."
 readme = "README.md"
 license = "MIT"
@@ -27,7 +27,7 @@ classifiers = [
 ]
 requires-python = ">=3.12"
 dependencies = [
-    "lambdafeedback-slr-parsing (>=0.3.0rc3,<0.4.0)",
+    "lambdafeedback-slr-parsing (>=0.3.0rc4,<0.4.0)",
     "sympy (>=1.14,<2.0)",
     "latex2sympy2-extended[antlr4-13-2] (>=1.11.0,<2.0)",
 ]
diff --git a/units/CHANGELOG.md b/physical_quantities/CHANGELOG.md
similarity index 95%
rename from units/CHANGELOG.md
rename to physical_quantities/CHANGELOG.md
index 364f076..601f98d 100644
--- a/units/CHANGELOG.md
+++ b/physical_quantities/CHANGELOG.md
@@ -1,11 +1,12 @@
-# Changelog: lambdafeedback-units
+# Changelog: lambdafeedback-physical-quantities
 
-## 0.3.0 (unreleased; pre-release 0.3.0rc3, tag v0.3.0-rc.3)
+## 0.3.0 (unreleased; pre-release 0.3.0rc4, tag v0.3.0-rc.4)
 
 The first public release. This is a further tidy-up after the 0.2.0 extraction: the package now only does unit conversion. Package metadata (MIT licence, README, URLs) is in place for PyPI. Python 3.13 and later is supported, now that `lambdafeedback-expression-parsing` no longer depends on latex2sympy2. SymPy 1.14 or later is required (was 1.12): 1.12 predates Python 3.12, and a configuration with a declared function (`symbol_assumptions` `function`) can only be pickled from 1.14.
 
 ### Breaking
 
+- (since 0.3.0rc4) **Renamed from `lambdafeedback-units` to `lambdafeedback-physical-quantities`.** The import path is `lambdafeedback.physical_quantities` (was `lambdafeedback.units`), and the repository subdirectory is `physical_quantities` (was `units`). The API is otherwise unchanged.
 - Requires Python 3.12 or later (3.11 is not supported).
 - `PhysicalQuantity.standard_values` is a tuple of expressions (several for a value such as `{1, 2}`), replacing `standard_value`, which was one expression or a set.
 
@@ -20,7 +21,7 @@ The first public release. This is a further tidy-up after the 0.2.0 extraction:
 - An unknown `strictness` raises `QuantityParamsError` (with `.field`). It is still an `ExpressionParsingError`, so existing handlers keep working.
 - `UNIT_SETS` and `CONVERSION_TO_BASE_SI` are read-only mappings (`MappingProxyType`). Assigning to them raises `TypeError`, where before it would have silently changed every cached parser.
 - `parse_quantity` and `preprocess_quantity` now take `QuantityParams` only; the `Mapping[str, Any]` (raw dict) fallback is gone, along with the `as_quantity_params` helper. Convert evaluation-function parameters explicitly at the call site with `QuantityParams.from_dict(evaluation_params)`.
-- `preview_function` and `fix_exponents` have moved out of this package entirely, to compareExpressions (`app/context/physical_quantity_preview.py`): building a LaTeX/SymPy preview string is an app-layer display concern, not unit conversion. Import them from there instead of `lambdafeedback.units`.
+- `preview_function` and `fix_exponents` have moved out of this package entirely, to compareExpressions (`app/context/physical_quantity_preview.py`): building a LaTeX/SymPy preview string is an app-layer display concern, not unit conversion. Import them from there instead of `lambdafeedback.physical_quantities`.
 - `preprocess_quantity` now returns a plain `str` (`expression_parsing.preprocess_expression`, which it matches the shape of, no longer returns `Preprocessed`).
 - `FeedbackTag` is removed, matching `expression_parsing`'s move from feedback tags to typed exceptions: mapping a parsing fact to feedback text is an app-layer concern, not this package's. `PhysicalQuantity.messages` (`(message_id, FeedbackTag)` pairs) is replaced by `PhysicalQuantity.reverted_units: tuple[RevertedUnit, ...]` — plain `before`/`marked`/`after` facts about unit-like text found inside a value, with no tag name or synthetic id. This isn't a raised exception (unlike `expression_parsing`'s failures): it's non-fatal and can fire multiple times per response, so it stays a collection.
 - **`PhysicalQuantity` is a frozen result.** Its attributes can't be set (`dataclasses.FrozenInstanceError`); `value`, `unit` and `ast_root` are still ordinary parse trees. `parse_quantity` builds it through the new `PhysicalQuantity.from_tree(name, params, ast_root, parser)`, which runs each step (splitting value from unit, restoring the value's text, LaTeX, SI forms) as a separate function; the constructor now takes every attribute. Quantities still compare by identity, and pickle and deep-copy without a custom `__getstate__`/`__setstate__`.
@@ -29,7 +30,7 @@ The first public release. This is a further tidy-up after the 0.2.0 extraction:
 
 ### Added
 
-- DEBUG logging through module loggers (`lambdafeedback.units.*`), with a `NullHandler` on the package logger; nothing is logged at INFO or above. See the repository README. `parse_quantity` logs the normalised text and the value/unit split.
+- DEBUG logging through module loggers (`lambdafeedback.physical_quantities.*`), with a `NullHandler` on the package logger; nothing is logged at INFO or above. See the repository README. `parse_quantity` logs the normalised text and the value/unit split.
 - `DisallowedUnitError` (see Breaking).
 - `PhysicalQuantity.base_dimension`: the dimension without the unit's factor (`5 km/h` gives `length/time`, where `dimension` is `10**3*length/((3600*time))`), and `same_dimension(a, b)` to compare two quantities' dimensions.
 - `MAX_INPUT_LENGTH` (10,000 characters): `parse_quantity` raises `QuantityParseError` for longer input, and `preprocess_quantity` returns it unchanged. This bounds the running time on any input.
@@ -62,7 +63,7 @@ The first public release. This is a further tidy-up after the 0.2.0 extraction:
 
 ### Changed
 
-- `quantity` keeps the public `PhysicalQuantity`, `RevertedUnit`, `parse_quantity` and `same_dimension`; the steps of reading a quantity are in private modules (`_split`, `_latex`, `_conversion`). Import public names from `lambdafeedback.units`: `MAX_UNIT_EXPONENT` is no longer in `lambdafeedback.units.quantity`.
+- `quantity` keeps the public `PhysicalQuantity`, `RevertedUnit`, `parse_quantity` and `same_dimension`; the steps of reading a quantity are in private modules (`_split`, `_latex`, `_conversion`). Import public names from `lambdafeedback.physical_quantities`: `MAX_UNIT_EXPONENT` is no longer in `lambdafeedback.physical_quantities.quantity`.
 - The regular expressions in preprocessing and parsing are replaced by string scanners, with the same results. The quantity grammar's tokens are `slr_parsing.Lexeme`s (requires `lambdafeedback-slr-parsing` with literal token patterns).
 
 ### Deprecated
diff --git a/units/LICENSE b/physical_quantities/LICENSE
similarity index 100%
rename from units/LICENSE
rename to physical_quantities/LICENSE
diff --git a/units/README.md b/physical_quantities/README.md
similarity index 93%
rename from units/README.md
rename to physical_quantities/README.md
index d6baa8d..79d888e 100644
--- a/units/README.md
+++ b/physical_quantities/README.md
@@ -1,4 +1,4 @@
-# lambdafeedback-units
+# lambdafeedback-physical-quantities
 
 Parse physical quantities such as `9.81 m/s^2` or `5 kilometres/hour` into a
 value and a unit, convert them to SI base units, and compare dimensions. Built
@@ -17,17 +17,17 @@ evaluation function.
 From git (not on PyPI yet):
 
 ```bash
-pip install "lambdafeedback-units @ git+https://github.com/lambda-feedback/lambda-feedback-packages.git@v0.3.0-rc.3#subdirectory=units"
+pip install "lambdafeedback-physical-quantities @ git+https://github.com/lambda-feedback/lambda-feedback-packages.git@v0.3.0-rc.4#subdirectory=physical_quantities"
 ```
 
 Install the packages it depends on (`slr_parsing`, `expression_parsing`) from the same tag; see the [repository README](../README.md#install).
 
-Requires Python 3.12 or later. The import root is `lambdafeedback.units`.
+Requires Python 3.12 or later. The import root is `lambdafeedback.physical_quantities`.
 
 ## Quick start
 
 ```python
-from lambdafeedback.units import QuantityParams, parse_quantity, same_dimension
+from lambdafeedback.physical_quantities import QuantityParams, parse_quantity, same_dimension
 
 q = parse_quantity("5 km/h", QuantityParams())
 q  # PhysicalQuantity(value='5', unit='kilometre/hour')
@@ -53,7 +53,7 @@ prefix spellings such as `μ`, `µ` and `deka`, and collapses whitespace.
 Without it, `2 µm` is read as a value with no unit.
 
 ```python
-from lambdafeedback.units import preprocess_quantity
+from lambdafeedback.physical_quantities import preprocess_quantity
 
 params = QuantityParams()
 text = preprocess_quantity("2 µm", params, name="response")  # '2 microm'
@@ -108,7 +108,7 @@ An invalid value raises `QuantityParamsError`, which is also an
 
 ## Units
 
-The tables are in `lambdafeedback.units` as tuples of named tuples:
+The tables are in `lambdafeedback.physical_quantities` as tuples of named tuples:
 `SI_PREFIXES`, `SI_BASE_UNITS`, `SI_DERIVED_UNITS`, `VERY_COMMON_UNITS`,
 `COMMON_UNITS` and `IMPERIAL_UNITS`. `UNIT_SETS` maps each set name to its
 units, and `CONVERSION_TO_BASE_SI` maps every (prefixed) unit name to its SI
@@ -137,7 +137,7 @@ All errors derive from `QuantityError`, which is a `ValueError`, and carry
 | `QuantityParamsError` | A `QuantityParams` field is invalid. |
 
 ```python
-from lambdafeedback.units import QuantityError
+from lambdafeedback.physical_quantities import QuantityError
 
 try:
     parse_quantity("2 m)", QuantityParams())
@@ -179,7 +179,7 @@ except QuantityError as error:
 
 ## Changelog
 
-See [CHANGELOG.md](https://github.com/lambda-feedback/lambda-feedback-packages/blob/main/units/CHANGELOG.md).
+See [CHANGELOG.md](https://github.com/lambda-feedback/lambda-feedback-packages/blob/main/physical_quantities/CHANGELOG.md).
 
 ## License
 
diff --git a/units/pyproject.toml b/physical_quantities/pyproject.toml
similarity index 83%
rename from units/pyproject.toml
rename to physical_quantities/pyproject.toml
index e03aff1..74e3d49 100644
--- a/units/pyproject.toml
+++ b/physical_quantities/pyproject.toml
@@ -3,8 +3,8 @@ requires = ["poetry-core>=2.2.0,<3.0.0"]
 build-backend = "poetry.core.masonry.api"
 
 [project]
-name = "lambdafeedback-units"
-version = "0.3.0rc3"
+name = "lambdafeedback-physical-quantities"
+version = "0.3.0rc4"
 description = "Parse physical quantities such as 9.81 m/s^2 into value and unit, with SI conversion and dimensional analysis."
 readme = "README.md"
 license = "MIT"
@@ -25,17 +25,17 @@ classifiers = [
 ]
 requires-python = ">=3.12"
 dependencies = [
-    "lambdafeedback-slr-parsing (>=0.3.0rc3,<0.4.0)",
-    "lambdafeedback-expression-parsing (>=0.3.0rc3,<0.4.0)",
+    "lambdafeedback-slr-parsing (>=0.3.0rc4,<0.4.0)",
+    "lambdafeedback-expression-parsing (>=0.3.0rc4,<0.4.0)",
     "sympy (>=1.14,<2.0)",
 ]
 
 [project.urls]
 Repository = "https://github.com/lambda-feedback/lambda-feedback-packages"
-Changelog = "https://github.com/lambda-feedback/lambda-feedback-packages/blob/main/units/CHANGELOG.md"
+Changelog = "https://github.com/lambda-feedback/lambda-feedback-packages/blob/main/physical_quantities/CHANGELOG.md"
 
 [tool.poetry]
-packages = [{ include = "lambdafeedback/units", from = "src" }]
+packages = [{ include = "lambdafeedback/physical_quantities", from = "src" }]
 # The source distribution also carries the changelog and the tests.
 include = [{ path = "CHANGELOG.md", format = "sdist" }, { path = "tests", format = "sdist" }]
 
diff --git a/units/src/lambdafeedback/units/__init__.py b/physical_quantities/src/lambdafeedback/physical_quantities/__init__.py
similarity index 97%
rename from units/src/lambdafeedback/units/__init__.py
rename to physical_quantities/src/lambdafeedback/physical_quantities/__init__.py
index d11501a..763aa4c 100644
--- a/units/src/lambdafeedback/units/__init__.py
+++ b/physical_quantities/src/lambdafeedback/physical_quantities/__init__.py
@@ -49,7 +49,7 @@
 logging.getLogger(__name__).addHandler(logging.NullHandler())
 
 try:
-    __version__ = version("lambdafeedback-units")
+    __version__ = version("lambdafeedback-physical-quantities")
 except PackageNotFoundError:  # running from a source checkout that isn't installed
     __version__ = "0+unknown"
 
diff --git a/units/src/lambdafeedback/units/_conversion.py b/physical_quantities/src/lambdafeedback/physical_quantities/_conversion.py
similarity index 97%
rename from units/src/lambdafeedback/units/_conversion.py
rename to physical_quantities/src/lambdafeedback/physical_quantities/_conversion.py
index ed13c2a..d69d173 100644
--- a/units/src/lambdafeedback/units/_conversion.py
+++ b/physical_quantities/src/lambdafeedback/physical_quantities/_conversion.py
@@ -60,7 +60,7 @@ def _expand_units(node: ExprNode, parser: SLRParser) -> ExprNode:
 
 
 class SympyForms(NamedTuple):
-    """The SymPy fields of a :class:`~lambdafeedback.units.PhysicalQuantity`."""
+    """The SymPy fields of a :class:`~lambdafeedback.physical_quantities.PhysicalQuantity`."""
 
     standard_values: tuple[Basic, ...] | None
     standard_unit: Basic | None
diff --git a/units/src/lambdafeedback/units/_latex.py b/physical_quantities/src/lambdafeedback/physical_quantities/_latex.py
similarity index 100%
rename from units/src/lambdafeedback/units/_latex.py
rename to physical_quantities/src/lambdafeedback/physical_quantities/_latex.py
diff --git a/units/src/lambdafeedback/units/_split.py b/physical_quantities/src/lambdafeedback/physical_quantities/_split.py
similarity index 100%
rename from units/src/lambdafeedback/units/_split.py
rename to physical_quantities/src/lambdafeedback/physical_quantities/_split.py
diff --git a/units/src/lambdafeedback/units/data.py b/physical_quantities/src/lambdafeedback/physical_quantities/data.py
similarity index 100%
rename from units/src/lambdafeedback/units/data.py
rename to physical_quantities/src/lambdafeedback/physical_quantities/data.py
diff --git a/units/src/lambdafeedback/units/errors.py b/physical_quantities/src/lambdafeedback/physical_quantities/errors.py
similarity index 89%
rename from units/src/lambdafeedback/units/errors.py
rename to physical_quantities/src/lambdafeedback/physical_quantities/errors.py
index b63e8ff..ea198d9 100644
--- a/units/src/lambdafeedback/units/errors.py
+++ b/physical_quantities/src/lambdafeedback/physical_quantities/errors.py
@@ -1,4 +1,4 @@
-"""Exceptions raised by the units package."""
+"""Exceptions raised by the physical quantities package."""
 
 from __future__ import annotations
 
@@ -6,7 +6,7 @@
 
 
 class QuantityError(ValueError):
-    """Base class for errors raised by the units package.
+    """Base class for errors raised by the physical quantities package.
 
     ``expression`` is the text being read, when known, and ``name`` (e.g.
     ``"response"``) identifies which quantity it was.
@@ -47,7 +47,7 @@ class UnitConversionError(QuantityError):
 
 
 class QuantityParamsError(QuantityError, ExpressionParsingError):
-    """A :class:`~lambdafeedback.units.QuantityParams` field is invalid; ``field`` is its name.
+    """A :class:`~lambdafeedback.physical_quantities.QuantityParams` field is invalid; ``field`` is its name.
 
     Also an ``ExpressionParsingError``, like the errors for the inherited
     :class:`~lambdafeedback.expression_parsing.ExpressionParams` fields.
diff --git a/units/src/lambdafeedback/units/params.py b/physical_quantities/src/lambdafeedback/physical_quantities/params.py
similarity index 92%
rename from units/src/lambdafeedback/units/params.py
rename to physical_quantities/src/lambdafeedback/physical_quantities/params.py
index 7bad0f8..0068618 100644
--- a/units/src/lambdafeedback/units/params.py
+++ b/physical_quantities/src/lambdafeedback/physical_quantities/params.py
@@ -13,7 +13,10 @@
 from .errors import QuantityParamsError
 
 MAX_INPUT_LENGTH = 10_000
-"""Longest input :func:`~lambdafeedback.units.parse_quantity` reads, in characters: a bound on its running time."""
+"""Longest input :func:`~lambdafeedback.physical_quantities.parse_quantity` reads, in characters.
+
+A bound on its running time.
+"""
 
 Strictness = Literal["strict", "natural"]
 """``strict``: only unit names and symbols, units separated by ``*`` / ``/`` / spaces;
@@ -28,7 +31,7 @@ class QuantityParams(ExpressionParams):
     legacy_preprocessing: bool = False
     """Deprecated (removed in 1.0): rewrite the response the way the old ``legacy`` strictness did."""
     unit_sets: frozenset[str] = frozenset(UNIT_SETS)
-    """Names from :data:`~lambdafeedback.units.data.UNIT_SETS` whose units are recognised."""
+    """Names from :data:`~lambdafeedback.physical_quantities.data.UNIT_SETS` whose units are recognised."""
 
     def __post_init__(self) -> None:
         super().__post_init__()
diff --git a/units/src/lambdafeedback/units/parser.py b/physical_quantities/src/lambdafeedback/physical_quantities/parser.py
similarity index 100%
rename from units/src/lambdafeedback/units/parser.py
rename to physical_quantities/src/lambdafeedback/physical_quantities/parser.py
diff --git a/units/src/lambdafeedback/units/preprocessing.py b/physical_quantities/src/lambdafeedback/physical_quantities/preprocessing.py
similarity index 98%
rename from units/src/lambdafeedback/units/preprocessing.py
rename to physical_quantities/src/lambdafeedback/physical_quantities/preprocessing.py
index a24e584..286fea1 100644
--- a/units/src/lambdafeedback/units/preprocessing.py
+++ b/physical_quantities/src/lambdafeedback/physical_quantities/preprocessing.py
@@ -26,8 +26,8 @@ def preprocess_quantity(expr: str, params: QuantityParams, *, name: str | None =
     Same shape as ``expression_parsing.preprocess_expression``, so either can
     serve as a context's preprocessing step. ``name`` is unused (nothing is raised).
 
-    Input longer than :data:`~lambdafeedback.units.MAX_INPUT_LENGTH` is
-    returned unchanged (:func:`~lambdafeedback.units.parse_quantity` rejects
+    Input longer than :data:`~lambdafeedback.physical_quantities.MAX_INPUT_LENGTH` is
+    returned unchanged (:func:`~lambdafeedback.physical_quantities.parse_quantity` rejects
     it), and so is input longer than :data:`MAX_LEGACY_LENGTH` with legacy
     preprocessing.
     """
diff --git a/units/src/lambdafeedback/units/py.typed b/physical_quantities/src/lambdafeedback/physical_quantities/py.typed
similarity index 100%
rename from units/src/lambdafeedback/units/py.typed
rename to physical_quantities/src/lambdafeedback/physical_quantities/py.typed
diff --git a/units/src/lambdafeedback/units/quantity.py b/physical_quantities/src/lambdafeedback/physical_quantities/quantity.py
similarity index 99%
rename from units/src/lambdafeedback/units/quantity.py
rename to physical_quantities/src/lambdafeedback/physical_quantities/quantity.py
index a5d82a6..bdf2e6d 100644
--- a/units/src/lambdafeedback/units/quantity.py
+++ b/physical_quantities/src/lambdafeedback/physical_quantities/quantity.py
@@ -94,7 +94,7 @@ class PhysicalQuantity:
     """A response read as a quantity: its value and unit, their LaTeX, and SI forms.
 
     Use :func:`parse_quantity` to create one. SymPy results use the SI base
-    units of :data:`~lambdafeedback.units.SI_BASE_UNITS` as symbols; mass is
+    units of :data:`~lambdafeedback.physical_quantities.SI_BASE_UNITS` as symbols; mass is
     in grams (``kilogram`` expands to ``1000*gram``).
 
     Its attributes can't be set (it is frozen), but ``value``, ``unit`` and
diff --git a/units/src/lambdafeedback/units/tags.py b/physical_quantities/src/lambdafeedback/physical_quantities/tags.py
similarity index 100%
rename from units/src/lambdafeedback/units/tags.py
rename to physical_quantities/src/lambdafeedback/physical_quantities/tags.py
diff --git a/units/src/lambdafeedback/units/text.py b/physical_quantities/src/lambdafeedback/physical_quantities/text.py
similarity index 100%
rename from units/src/lambdafeedback/units/text.py
rename to physical_quantities/src/lambdafeedback/physical_quantities/text.py
diff --git a/units/tests/__init__.py b/physical_quantities/tests/__init__.py
similarity index 100%
rename from units/tests/__init__.py
rename to physical_quantities/tests/__init__.py
diff --git a/units/tests/_fixtures.py b/physical_quantities/tests/_fixtures.py
similarity index 88%
rename from units/tests/_fixtures.py
rename to physical_quantities/tests/_fixtures.py
index 61b9302..e826b25 100644
--- a/units/tests/_fixtures.py
+++ b/physical_quantities/tests/_fixtures.py
@@ -1,4 +1,4 @@
-"""Test fixtures for the units package.
+"""Test fixtures for the physical quantities package.
 
 ``default_parameters`` mirrors the quantity-specific defaults of the
 physical-quantity context in compareExpressions (app/context/physical_quantity.py);
diff --git a/units/tests/test_api.py b/physical_quantities/tests/test_api.py
similarity index 96%
rename from units/tests/test_api.py
rename to physical_quantities/tests/test_api.py
index fa9deac..719cf54 100644
--- a/units/tests/test_api.py
+++ b/physical_quantities/tests/test_api.py
@@ -3,9 +3,9 @@
 import pytest
 from sympy import Rational, simplify
 
-import lambdafeedback.units
+import lambdafeedback.physical_quantities
 from lambdafeedback.expression_parsing import ExpressionParsingError
-from lambdafeedback.units import (
+from lambdafeedback.physical_quantities import (
     ALL_UNITS,
     CONVERSION_TO_BASE_SI,
     SI_BASE_UNITS,
@@ -26,7 +26,7 @@
 
 
 def test_version():
-    assert isinstance(lambdafeedback.units.__version__, str)
+    assert isinstance(lambdafeedback.physical_quantities.__version__, str)
 
 
 class TestQuantityParams:
@@ -299,8 +299,10 @@ def test_unicode_product_signs_are_products(self, sign):
 def test_parse_quantity_logs_the_value_unit_split(caplog):
     import logging
 
-    with caplog.at_level(logging.DEBUG, logger="lambdafeedback.units"):
+    with caplog.at_level(logging.DEBUG, logger="lambdafeedback.physical_quantities"):
         parse_quantity("9.81 m/s^2", QuantityParams())
-    messages = [record.getMessage() for record in caplog.records if record.name.startswith("lambdafeedback.units")]
+    messages = [
+        record.getMessage() for record in caplog.records if record.name.startswith("lambdafeedback.physical_quantities")
+    ]
     assert "split '9.81 m/s^2' into value '9.81' and unit 'metre/second^2'" in messages
     assert all(record.levelno < logging.WARNING for record in caplog.records)
diff --git a/units/tests/test_regressions.py b/physical_quantities/tests/test_regressions.py
similarity index 96%
rename from units/tests/test_regressions.py
rename to physical_quantities/tests/test_regressions.py
index 899d60c..53e4ae4 100644
--- a/units/tests/test_regressions.py
+++ b/physical_quantities/tests/test_regressions.py
@@ -3,8 +3,7 @@
 import pytest
 from sympy import Basic, simplify
 
-from lambdafeedback.slr_parsing import GROUP_LABEL, ExprNode
-from lambdafeedback.units import (
+from lambdafeedback.physical_quantities import (
     DisallowedUnitError,
     PhysicalQuantity,
     QuantityParams,
@@ -13,8 +12,9 @@
     build_quantity_parser,
     parse_quantity,
 )
-from lambdafeedback.units._split import split_value_and_unit
-from lambdafeedback.units.quantity import _revert_value_text
+from lambdafeedback.physical_quantities._split import split_value_and_unit
+from lambdafeedback.physical_quantities.quantity import _revert_value_text
+from lambdafeedback.slr_parsing import GROUP_LABEL, ExprNode
 
 NATURAL = QuantityParams(strictness="natural")
 
@@ -228,7 +228,7 @@ class TestPickling:
     def test_params_error_round_trips(self):
         import pickle
 
-        from lambdafeedback.units import QuantityParamsError
+        from lambdafeedback.physical_quantities import QuantityParamsError
 
         # The default reduce called QuantityParamsError(formatted_message), which needs two arguments.
         error = pickle.loads(pickle.dumps(QuantityParamsError("strictness", "bad")))
@@ -257,7 +257,7 @@ def comparable(value):
             assert comparable(getattr(copy, field.name)) == comparable(getattr(quantity, field.name)), field.name
 
     def test_parser_is_deprecated_and_still_the_cached_parser(self):
-        from lambdafeedback.units import build_quantity_parser
+        from lambdafeedback.physical_quantities import build_quantity_parser
 
         quantity = parse("5 km/h")
         with pytest.deprecated_call(match="PhysicalQuantity.parser"):
@@ -302,13 +302,13 @@ def test_raise_quickly(self, expr):
 
 class TestInputLimits:
     def test_input_at_the_cap_is_read(self):
-        from lambdafeedback.units import MAX_INPUT_LENGTH
+        from lambdafeedback.physical_quantities import MAX_INPUT_LENGTH
 
         expr = "2 m".ljust(MAX_INPUT_LENGTH)
         assert parse(expr).unit.content_string() == "metre"
 
     def test_input_over_the_cap_raises(self):
-        from lambdafeedback.units import MAX_INPUT_LENGTH
+        from lambdafeedback.physical_quantities import MAX_INPUT_LENGTH
 
         with pytest.raises(QuantityParseError, match="too long"):
             parse("2 m".ljust(MAX_INPUT_LENGTH + 1))
@@ -316,7 +316,7 @@ def test_input_over_the_cap_raises(self):
     def test_preprocessing_passes_over_long_input_through(self):
         import time
 
-        from lambdafeedback.units import MAX_INPUT_LENGTH, preprocess_quantity
+        from lambdafeedback.physical_quantities import MAX_INPUT_LENGTH, preprocess_quantity
 
         expr = "5 μ s " * (MAX_INPUT_LENGTH // 6 + 1)
         start = time.perf_counter()
@@ -328,7 +328,7 @@ def test_legacy_rewrites_skip_long_input(self):
         import time
         import warnings
 
-        from lambdafeedback.units import MAX_LEGACY_LENGTH, preprocess_quantity
+        from lambdafeedback.physical_quantities import MAX_LEGACY_LENGTH, preprocess_quantity
 
         with warnings.catch_warnings():
             warnings.simplefilter("ignore", DeprecationWarning)
diff --git a/units/tests/test_scanners.py b/physical_quantities/tests/test_scanners.py
similarity index 89%
rename from units/tests/test_scanners.py
rename to physical_quantities/tests/test_scanners.py
index bf56fc3..8791aee 100644
--- a/units/tests/test_scanners.py
+++ b/physical_quantities/tests/test_scanners.py
@@ -2,10 +2,10 @@
 
 import pytest
 
-from lambdafeedback.units import QuantityParams
-from lambdafeedback.units.parser import _number_prefix
-from lambdafeedback.units.preprocessing import transform_prefixes_to_standard
-from lambdafeedback.units.text import (
+from lambdafeedback.physical_quantities import QuantityParams
+from lambdafeedback.physical_quantities.parser import _number_prefix
+from lambdafeedback.physical_quantities.preprocessing import transform_prefixes_to_standard
+from lambdafeedback.physical_quantities.text import (
     called_names,
     collapse_whitespace,
     mentions_celsius_or_fahrenheit,
diff --git a/units/tests/test_slr_quantity.py b/physical_quantities/tests/test_slr_quantity.py
similarity index 99%
rename from units/tests/test_slr_quantity.py
rename to physical_quantities/tests/test_slr_quantity.py
index 2e28304..1f5608f 100644
--- a/units/tests/test_slr_quantity.py
+++ b/physical_quantities/tests/test_slr_quantity.py
@@ -2,7 +2,7 @@
 
 import pytest
 
-from lambdafeedback.units import (
+from lambdafeedback.physical_quantities import (
     COMMON_UNITS,
     IMPERIAL_UNITS,
     SI_BASE_UNITS,
diff --git a/poetry.lock b/poetry.lock
index 70f2fc4..772deff 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -1278,7 +1278,7 @@ type = ["pygobject-stubs", "pytest-mypy (>=1.0.1)", "shtab", "types-pywin32"]
 
 [[package]]
 name = "lambdafeedback-criteria"
-version = "0.3.0rc3"
+version = "0.3.0rc4"
 description = "Criteria parser and criteria graphs that turn evaluations into feedback, for Lambda Feedback evaluation functions."
 optional = false
 python-versions = ">=3.12"
@@ -1287,7 +1287,7 @@ files = []
 develop = true
 
 [package.dependencies]
-lambdafeedback-slr-parsing = ">=0.3.0rc3,<0.4.0"
+lambdafeedback-slr-parsing = ">=0.3.0rc4,<0.4.0"
 
 [package.source]
 type = "directory"
@@ -1295,7 +1295,7 @@ url = "criteria"
 
 [[package]]
 name = "lambdafeedback-expression-parsing"
-version = "0.3.0rc3"
+version = "0.3.0rc4"
 description = "Safe SymPy parsing and preprocessing of learner-written mathematical expressions, for Lambda Feedback evaluation functions."
 optional = false
 python-versions = ">=3.12"
@@ -1304,7 +1304,7 @@ files = []
 develop = true
 
 [package.dependencies]
-lambdafeedback-slr-parsing = ">=0.3.0rc3,<0.4.0"
+lambdafeedback-slr-parsing = ">=0.3.0rc4,<0.4.0"
 latex2sympy2-extended = {version = ">=1.11.0,<2.0", extras = ["antlr4-13-2"]}
 sympy = ">=1.14,<2.0"
 
@@ -1313,37 +1313,37 @@ type = "directory"
 url = "expression_parsing"
 
 [[package]]
-name = "lambdafeedback-slr-parsing"
-version = "0.3.0rc3"
-description = "Dependency-free SLR(1) parser generator for Lambda Feedback evaluation functions."
+name = "lambdafeedback-physical-quantities"
+version = "0.3.0rc4"
+description = "Parse physical quantities such as 9.81 m/s^2 into value and unit, with SI conversion and dimensional analysis."
 optional = false
 python-versions = ">=3.12"
 groups = ["dev"]
 files = []
 develop = true
 
+[package.dependencies]
+lambdafeedback-expression-parsing = ">=0.3.0rc4,<0.4.0"
+lambdafeedback-slr-parsing = ">=0.3.0rc4,<0.4.0"
+sympy = ">=1.14,<2.0"
+
 [package.source]
 type = "directory"
-url = "slr_parsing"
+url = "physical_quantities"
 
 [[package]]
-name = "lambdafeedback-units"
-version = "0.3.0rc3"
-description = "Parse physical quantities such as 9.81 m/s^2 into value and unit, with SI conversion and dimensional analysis."
+name = "lambdafeedback-slr-parsing"
+version = "0.3.0rc4"
+description = "Dependency-free SLR(1) parser generator for Lambda Feedback evaluation functions."
 optional = false
 python-versions = ">=3.12"
 groups = ["dev"]
 files = []
 develop = true
 
-[package.dependencies]
-lambdafeedback-expression-parsing = ">=0.3.0rc3,<0.4.0"
-lambdafeedback-slr-parsing = ">=0.3.0rc3,<0.4.0"
-sympy = ">=1.14,<2.0"
-
 [package.source]
 type = "directory"
-url = "units"
+url = "slr_parsing"
 
 [[package]]
 name = "latex2sympy2-extended"
@@ -3022,4 +3022,4 @@ test = ["pytest"]
 [metadata]
 lock-version = "2.1"
 python-versions = ">=3.12,<4.0"
-content-hash = "460ca14f1e861782181fed3d0d60a56c1187a6f763f03ae02fc0509c5b75d856"
+content-hash = "4458d98f8a00e762ea2898865298a056a925638e5cc5ba54126fbe7dd98eb185"
diff --git a/pyproject.toml b/pyproject.toml
index ce7715e..a64b757 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -13,7 +13,7 @@ package-mode = false
 lambdafeedback-slr-parsing = { path = "slr_parsing", develop = true }
 lambdafeedback-criteria = { path = "criteria", develop = true }
 lambdafeedback-expression-parsing = { path = "expression_parsing", develop = true }
-lambdafeedback-units = { path = "units", develop = true }
+lambdafeedback-physical-quantities = { path = "physical_quantities", develop = true }
 # Dev-only: tests check the criteria feedback helpers against the real
 # lf_toolkit Result. Not a runtime dependency until lf_toolkit stops shipping
 # its dev tools as runtime requirements (docs/upstream-lf-toolkit.md).
@@ -55,7 +55,7 @@ known-first-party = ["lambdafeedback"]
 
 [tool.mypy]
 python_version = "3.12"
-files = ["scripts/check_dist.py", "scripts/release_version.py", "tools/parity/corpus.py", "tools/parity/check.py", "slr_parsing/src", "criteria/src", "expression_parsing/src", "units/src"]
+files = ["scripts/check_dist.py", "scripts/release_version.py", "tools/parity/corpus.py", "tools/parity/check.py", "slr_parsing/src", "criteria/src", "expression_parsing/src", "physical_quantities/src"]
 namespace_packages = true
 explicit_package_bases = true
 mypy_path = [
@@ -63,7 +63,7 @@ mypy_path = [
     "slr_parsing/src",
     "criteria/src",
     "expression_parsing/src",
-    "units/src",
+    "physical_quantities/src",
 ]
 warn_unused_configs = true
 warn_redundant_casts = true
@@ -77,8 +77,8 @@ module = [
     "lambdafeedback.slr_parsing.*",
     "lambdafeedback.criteria",
     "lambdafeedback.criteria.*",
-    "lambdafeedback.units",
-    "lambdafeedback.units.*",
+    "lambdafeedback.physical_quantities",
+    "lambdafeedback.physical_quantities.*",
 ]
 disallow_untyped_defs = true
 disallow_incomplete_defs = true
diff --git a/scripts/check_dist.py b/scripts/check_dist.py
index 39f0b6a..78d5b30 100644
--- a/scripts/check_dist.py
+++ b/scripts/check_dist.py
@@ -22,12 +22,12 @@
 from pathlib import Path
 
 ROOT = Path(__file__).resolve().parent.parent
-PACKAGES = ("slr_parsing", "criteria", "expression_parsing", "units")
+PACKAGES = ("slr_parsing", "criteria", "expression_parsing", "physical_quantities")
 
 SMOKE_TEST = """
 from lambdafeedback.criteria import build_criteria_parser
 from lambdafeedback.expression_parsing import ExpressionParams, SympyParsingConfig, parse_expression
-from lambdafeedback.units import QuantityParams, parse_quantity
+from lambdafeedback.physical_quantities import QuantityParams, parse_quantity
 from lambdafeedback.slr_parsing import SLRParser
 
 assert str(parse_expression("2x+1", SympyParsingConfig.from_params(ExpressionParams()))) == "2*x + 1"
diff --git a/scripts/release_version.py b/scripts/release_version.py
index 028f2cb..5881814 100644
--- a/scripts/release_version.py
+++ b/scripts/release_version.py
@@ -23,7 +23,7 @@
 from typing import NamedTuple
 
 ROOT = Path(__file__).resolve().parent.parent
-PACKAGES = ("slr_parsing", "criteria", "expression_parsing", "units")
+PACKAGES = ("slr_parsing", "criteria", "expression_parsing", "physical_quantities")
 # Semantic-version pre-release labels and their PEP 440 spellings, in release order.
 PRE_RELEASE_LABELS = {"alpha": "a", "beta": "b", "rc": "rc"}
 
diff --git a/scripts/test.sh b/scripts/test.sh
index 9fc27ed..2f71558 100755
--- a/scripts/test.sh
+++ b/scripts/test.sh
@@ -6,7 +6,7 @@
 #   poetry run scripts/test.sh -q
 set -e
 cd "$(dirname "$0")/.."
-for pkg in slr_parsing criteria expression_parsing units; do
+for pkg in slr_parsing criteria expression_parsing physical_quantities; do
     echo "== $pkg"
     pytest "$pkg/tests" "$@"
 done
diff --git a/slr_parsing/CHANGELOG.md b/slr_parsing/CHANGELOG.md
index a60f512..77b1c66 100644
--- a/slr_parsing/CHANGELOG.md
+++ b/slr_parsing/CHANGELOG.md
@@ -1,6 +1,6 @@
 # Changelog: lambdafeedback-slr-parsing
 
-## 0.3.0 (unreleased; pre-release 0.3.0rc3, tag v0.3.0-rc.3)
+## 0.3.0 (unreleased; pre-release 0.3.0rc4, tag v0.3.0-rc.4)
 
 The first public release, after the extraction refactor. The import path is now `lambdafeedback.slr_parsing` (was `slr_parsing`). There was no 0.2.0 release: all four `lambdafeedback-*` packages share one version, and the first release is 0.3.0. Supports Python 3.12 to 3.14 (3.11 is not supported); `__version__` gives the installed version.
 
diff --git a/slr_parsing/README.md b/slr_parsing/README.md
index 142c150..8f21795 100644
--- a/slr_parsing/README.md
+++ b/slr_parsing/README.md
@@ -17,7 +17,7 @@ evaluation function.
 From git (not on PyPI yet):
 
 ```bash
-pip install "lambdafeedback-slr-parsing @ git+https://github.com/lambda-feedback/lambda-feedback-packages.git@v0.3.0-rc.3#subdirectory=slr_parsing"
+pip install "lambdafeedback-slr-parsing @ git+https://github.com/lambda-feedback/lambda-feedback-packages.git@v0.3.0-rc.4#subdirectory=slr_parsing"
 ```
 
 Requires Python 3.12+. The import root is `lambdafeedback.slr_parsing`.
diff --git a/slr_parsing/pyproject.toml b/slr_parsing/pyproject.toml
index 424023c..e3e1c9e 100644
--- a/slr_parsing/pyproject.toml
+++ b/slr_parsing/pyproject.toml
@@ -4,7 +4,7 @@ build-backend = "poetry.core.masonry.api"
 
 [project]
 name = "lambdafeedback-slr-parsing"
-version = "0.3.0rc3"
+version = "0.3.0rc4"
 description = "Dependency-free SLR(1) parser generator for Lambda Feedback evaluation functions."
 readme = "README.md"
 license = "MIT"
diff --git a/tools/parity/check.py b/tools/parity/check.py
index de91da9..2d1a7ec 100644
--- a/tools/parity/check.py
+++ b/tools/parity/check.py
@@ -43,7 +43,7 @@
     parse_expressions,
     sympy_to_latex,
 )
-from lambdafeedback.units import QuantityParams, parse_quantity  # noqa: E402
+from lambdafeedback.physical_quantities import QuantityParams, parse_quantity  # noqa: E402
 
 ERROR = "ERROR"