diff --git a/lib/matplotlib/axes/_axes.py b/lib/matplotlib/axes/_axes.py
index 7acfb23cf366..64ee4a512236 100644
--- a/lib/matplotlib/axes/_axes.py
+++ b/lib/matplotlib/axes/_axes.py
@@ -4418,7 +4418,7 @@ def scatter(self, x, y, s=None, c=None, marker=None, cmap=None, norm=None,
             The data positions.
 
         s : float or array-like, shape (n, ), optional
-            The marker size in points**2.
+            The marker size in points**2 (typographic points are 1/72 in.).
             Default is ``rcParams['lines.markersize'] ** 2``.
 
         c : array-like or list of colors or color, optional