diff --git a/lib/matplotlib/_docstring.py b/lib/matplotlib/_docstring.py
index 5ec19c08ef1b..f16c0bb8f0ef 100644
--- a/lib/matplotlib/_docstring.py
+++ b/lib/matplotlib/_docstring.py
@@ -85,24 +85,39 @@ def __missing__(self, key):
 
 class _ArtistPropertiesSubstitution:
     """
-    A `.Substitution` with two additional features:
-
-    - Substitutions of the form ``%(classname:kwdoc)s`` (ending with the
-      literal ":kwdoc" suffix) trigger lookup of an Artist subclass with the
-      given *classname*, and are substituted with the `.kwdoc` of that class.
-    - Decorating a class triggers substitution both on the class docstring and
-      on the class' ``__init__`` docstring (which is a commonly required
-      pattern for Artist subclasses).
+    A class to substitute formatted placeholders in docstrings.
+
+    This is realized in a single instance ``_docstring.interpd``.
+
+    Use `~._ArtistPropertiesSubstition.register` to define placeholders and
+    their substitution, e.g. ``_docstring.interpd.register(name="some value")``.
+
+    Use this as a decorator to apply the substitution::
+
+        @_docstring.interpd
+        def some_func():
+            '''Replace %(name)s.'''
+
+    Decorating a class triggers substitution both on the class docstring and
+    on the class' ``__init__`` docstring (which is a commonly required
+    pattern for Artist subclasses).
+
+    Substitutions of the form ``%(classname:kwdoc)s`` (ending with the
+    literal ":kwdoc" suffix) trigger lookup of an Artist subclass with the
+    given *classname*, and are substituted with the `.kwdoc` of that class.
     """
 
     def __init__(self):
         self.params = _ArtistKwdocLoader()
 
-    def update(self, *args, **kwargs):
+    def register(self, **kwargs):
         """
-        Update ``self.params`` (which must be a dict) with the supplied args.
+        Register substitutions.
+
+        ``_docstring.interpd.register(name="some value")`` makes "name" available
+        as a named parameter that will be replaced by "some value".
         """
-        self.params.update(*args, **kwargs)
+        self.params.update(**kwargs)
 
     def __call__(self, obj):
         if obj.__doc__:
diff --git a/lib/matplotlib/_docstring.pyi b/lib/matplotlib/_docstring.pyi
index b776d4b4dbe3..fb52d0846123 100644
--- a/lib/matplotlib/_docstring.pyi
+++ b/lib/matplotlib/_docstring.pyi
@@ -23,7 +23,7 @@ class _ArtistKwdocLoader(dict[str, str]):
 
 class _ArtistPropertiesSubstitution:
     def __init__(self) -> None: ...
-    def update(self, *args, **kwargs) -> None:
+    def register(self, **kwargs) -> None: ...
     def __call__(self, obj: _T) -> _T: ...
 
 
diff --git a/lib/matplotlib/_enums.py b/lib/matplotlib/_enums.py
index c8c50f7c3028..773011d36bf6 100644
--- a/lib/matplotlib/_enums.py
+++ b/lib/matplotlib/_enums.py
@@ -181,5 +181,7 @@ def demo():
         + ", ".join([f"'{cs.name}'" for cs in CapStyle]) \
         + "}"
 
-_docstring.interpd.update({'JoinStyle': JoinStyle.input_description,
-                          'CapStyle': CapStyle.input_description})
+_docstring.interpd.register(
+    JoinStyle=JoinStyle.input_description,
+    CapStyle=CapStyle.input_description,
+)
diff --git a/lib/matplotlib/axes/_secondary_axes.py b/lib/matplotlib/axes/_secondary_axes.py
index b01acc4b127d..15a1970fa4a6 100644
--- a/lib/matplotlib/axes/_secondary_axes.py
+++ b/lib/matplotlib/axes/_secondary_axes.py
@@ -319,4 +319,4 @@ def set_color(self, color):
 **kwargs : `~matplotlib.axes.Axes` properties.
     Other miscellaneous Axes parameters.
 '''
-_docstring.interpd.update(_secax_docstring=_secax_docstring)
+_docstring.interpd.register(_secax_docstring=_secax_docstring)
diff --git a/lib/matplotlib/cm.py b/lib/matplotlib/cm.py
index 025cb84db1d7..27333f8dba8a 100644
--- a/lib/matplotlib/cm.py
+++ b/lib/matplotlib/cm.py
@@ -651,7 +651,7 @@ def _format_cursor_data_override(self, data):
 
 
 # The docstrings here must be generic enough to apply to all relevant methods.
-mpl._docstring.interpd.update(
+mpl._docstring.interpd.register(
     cmap_doc="""\
 cmap : str or `~matplotlib.colors.Colormap`, default: :rc:`image.cmap`
     The Colormap instance or registered colormap name used to map scalar data
diff --git a/lib/matplotlib/colorbar.py b/lib/matplotlib/colorbar.py
index 296f072a4af1..2d2fe42dd16a 100644
--- a/lib/matplotlib/colorbar.py
+++ b/lib/matplotlib/colorbar.py
@@ -26,7 +26,7 @@
 
 _log = logging.getLogger(__name__)
 
-_docstring.interpd.update(
+_docstring.interpd.register(
     _make_axes_kw_doc="""
 location : None or {'left', 'right', 'top', 'bottom'}
     The location, relative to the parent Axes, where the colorbar Axes
diff --git a/lib/matplotlib/contour.py b/lib/matplotlib/contour.py
index 9ad4cd4f2752..cb8846688372 100644
--- a/lib/matplotlib/contour.py
+++ b/lib/matplotlib/contour.py
@@ -536,7 +536,7 @@ def _find_closest_point_on_path(xys, p):
     return (d2s[imin], projs[imin], (imin, imin+1))
 
 
-_docstring.interpd.update(contour_set_attributes=r"""
+_docstring.interpd.register(contour_set_attributes=r"""
 Attributes
 ----------
 ax : `~matplotlib.axes.Axes`
@@ -1445,7 +1445,7 @@ def _initialize_x_y(self, z):
         return np.meshgrid(x, y)
 
 
-_docstring.interpd.update(contour_doc="""
+_docstring.interpd.register(contour_doc="""
 `.contour` and `.contourf` draw contour lines and filled contours,
 respectively.  Except as noted, function signatures and return values
 are the same for both versions.
diff --git a/lib/matplotlib/legend.py b/lib/matplotlib/legend.py
index 7ef328e2007c..f411a4c118dd 100644
--- a/lib/matplotlib/legend.py
+++ b/lib/matplotlib/legend.py
@@ -305,7 +305,7 @@ def _update_bbox_to_anchor(self, loc_in_canvas):
     _loc_doc_base.format(parent='axes', default=':rc:`legend.loc`',
                          best=_loc_doc_best, outside='') +
     _legend_kw_doc_base)
-_docstring.interpd.update(_legend_kw_axes=_legend_kw_axes_st)
+_docstring.interpd.register(_legend_kw_axes=_legend_kw_axes_st)
 
 _outside_doc = """
     If a figure is using the constrained layout manager, the string codes
@@ -323,20 +323,20 @@ def _update_bbox_to_anchor(self, loc_in_canvas):
     _loc_doc_base.format(parent='figure', default="'upper right'",
                          best='', outside=_outside_doc) +
     _legend_kw_doc_base)
-_docstring.interpd.update(_legend_kw_figure=_legend_kw_figure_st)
+_docstring.interpd.register(_legend_kw_figure=_legend_kw_figure_st)
 
 _legend_kw_both_st = (
     _loc_doc_base.format(parent='axes/figure',
                          default=":rc:`legend.loc` for Axes, 'upper right' for Figure",
                          best=_loc_doc_best, outside=_outside_doc) +
     _legend_kw_doc_base)
-_docstring.interpd.update(_legend_kw_doc=_legend_kw_both_st)
+_docstring.interpd.register(_legend_kw_doc=_legend_kw_both_st)
 
 _legend_kw_set_loc_st = (
     _loc_doc_base.format(parent='axes/figure',
                          default=":rc:`legend.loc` for Axes, 'upper right' for Figure",
                          best=_loc_doc_best, outside=_outside_doc))
-_docstring.interpd.update(_legend_kw_set_loc_doc=_legend_kw_set_loc_st)
+_docstring.interpd.register(_legend_kw_set_loc_doc=_legend_kw_set_loc_st)
 
 
 class Legend(Artist):
diff --git a/lib/matplotlib/mlab.py b/lib/matplotlib/mlab.py
index e1f08c0da5ce..7b774a80afa5 100644
--- a/lib/matplotlib/mlab.py
+++ b/lib/matplotlib/mlab.py
@@ -400,7 +400,7 @@ def _single_spectrum_helper(
 
 
 # Split out these keyword docs so that they can be used elsewhere
-_docstring.interpd.update(
+_docstring.interpd.register(
     Spectral="""\
 Fs : float, default: 2
     The sampling frequency (samples per time unit).  It is used to calculate
diff --git a/lib/matplotlib/patches.py b/lib/matplotlib/patches.py
index 0d5867e08ae1..b5be4e9cfab0 100644
--- a/lib/matplotlib/patches.py
+++ b/lib/matplotlib/patches.py
@@ -1552,7 +1552,7 @@ def _make_verts(self):
             ]
 
 
-_docstring.interpd.update(
+_docstring.interpd.register(
     FancyArrow="\n".join(
         (inspect.getdoc(FancyArrow.__init__) or "").splitlines()[2:]))
 
@@ -2290,7 +2290,7 @@ def __init_subclass__(cls):
         # - %(BoxStyle:table_and_accepts)s
         # - %(ConnectionStyle:table_and_accepts)s
         # - %(ArrowStyle:table_and_accepts)s
-        _docstring.interpd.update({
+        _docstring.interpd.register(**{
             f"{cls.__name__}:table": cls.pprint_styles(),
             f"{cls.__name__}:table_and_accepts": (
                 cls.pprint_styles()
diff --git a/lib/matplotlib/projections/__init__.py b/lib/matplotlib/projections/__init__.py
index b58d1ceb754d..f7b46192a84e 100644
--- a/lib/matplotlib/projections/__init__.py
+++ b/lib/matplotlib/projections/__init__.py
@@ -123,4 +123,4 @@ def get_projection_class(projection=None):
 
 
 get_projection_names = projection_registry.get_projection_names
-_docstring.interpd.update(projection_names=get_projection_names())
+_docstring.interpd.register(projection_names=get_projection_names())
diff --git a/lib/matplotlib/quiver.py b/lib/matplotlib/quiver.py
index 16c8a2195f67..c7408476c784 100644
--- a/lib/matplotlib/quiver.py
+++ b/lib/matplotlib/quiver.py
@@ -230,7 +230,7 @@
   of the head in forward direction so that the arrow head looks broken.
 """ % _docstring.interpd.params
 
-_docstring.interpd.update(quiver_doc=_quiver_doc)
+_docstring.interpd.register(quiver_doc=_quiver_doc)
 
 
 class QuiverKey(martist.Artist):
@@ -865,7 +865,7 @@ def _h_arrows(self, length):
     %(PolyCollection:kwdoc)s
 """ % _docstring.interpd.params
 
-_docstring.interpd.update(barbs_doc=_barbs_doc)
+_docstring.interpd.register(barbs_doc=_barbs_doc)
 
 
 class Barbs(mcollections.PolyCollection):
diff --git a/lib/matplotlib/scale.py b/lib/matplotlib/scale.py
index 7f90362b574b..d80ef9828fcd 100644
--- a/lib/matplotlib/scale.py
+++ b/lib/matplotlib/scale.py
@@ -750,7 +750,7 @@ def _get_scale_docs():
     return "\n".join(docs)
 
 
-_docstring.interpd.update(
+_docstring.interpd.register(
     scale_type='{%s}' % ', '.join([repr(x) for x in get_scale_names()]),
     scale_docs=_get_scale_docs().rstrip(),
     )
diff --git a/lib/matplotlib/text.py b/lib/matplotlib/text.py
index 6f59ca669d21..825e33d09add 100644
--- a/lib/matplotlib/text.py
+++ b/lib/matplotlib/text.py
@@ -2030,4 +2030,4 @@ def get_tightbbox(self, renderer=None):
         return super().get_tightbbox(renderer)
 
 
-_docstring.interpd.update(Annotation=Annotation.__init__.__doc__)
+_docstring.interpd.register(Annotation=Annotation.__init__.__doc__)
diff --git a/lib/matplotlib/tri/_tricontour.py b/lib/matplotlib/tri/_tricontour.py
index 1db3715d01af..bf96a8eb42a3 100644
--- a/lib/matplotlib/tri/_tricontour.py
+++ b/lib/matplotlib/tri/_tricontour.py
@@ -79,7 +79,7 @@ def _contour_args(self, args, kwargs):
         return (tri, z)
 
 
-_docstring.interpd.update(_tricontour_doc="""
+_docstring.interpd.register(_tricontour_doc="""
 Draw contour %%(type)s on an unstructured triangular grid.
 
 Call signatures::