diff --git a/python-spec/src/somacore/experiment.py b/python-spec/src/somacore/experiment.py
index a073206..13b540b 100644
--- a/python-spec/src/somacore/experiment.py
+++ b/python-spec/src/somacore/experiment.py
@@ -70,8 +70,8 @@ class Experiment(
     """A dataframe that stores the presence of obs in the spatial scenes.
 
     This provides a join table for the obs ``soma_joinid`` and the scene names used in
-    the ``spatial`` collection. This dataframe must contain dimensions ``soma_joinid``
-    and ``scene_id``. The ``scene_id`` dimension must be a ``string`` dimension. The
+    the ``spatial`` collection. This dataframe must contain index columns ``soma_joinid``
+    and ``scene_id``. The ``scene_id`` column must have type ``string``. The
     dataframe must contain a ``boolean`` column ``data``. The values of ``data`` are
     ``True`` if the obs with obsid ``soma_joinid`` is contained in the scene
     ``scene_id`` and ``False`` otherwise.
diff --git a/python-spec/src/somacore/measurement.py b/python-spec/src/somacore/measurement.py
index 5bb692f..4d9c944 100644
--- a/python-spec/src/somacore/measurement.py
+++ b/python-spec/src/somacore/measurement.py
@@ -104,8 +104,8 @@ class Measurement(
     """A dataframe that stores the presence of var in the spatial scenes.
 
     This provides a join tabel for the var ``soma_joinid`` and the scene names used in
-    the ``spatial`` collection. This dataframe must contain dimensions ``soma_joinid``
-    and ``scene_id``. The ``scene_id`` dimension must be a ``string`` dimension. The
+    the ``spatial`` collection. This dataframe must contain index columns ``soma_joinid``
+    and ``scene_id``. The ``scene_id`` column  must have type ``string``. The
     dataframe must contain a ``boolean`` column ``data``. The values of ``data`` are
     ``True`` if the var with varid ``soma_joinid`` is contained in scene with name
     ``scene_id`` and ``False`` otherwise.