Clarify "cardinality of" as "number of elements in" as many readers do

not have a math vocabulary.

diff --git a/Doc/library/stdtypes.rst b/Doc/library/stdtypes.rst
index 774b0c6230a5d82ffb62864dd8e6afb33ae2ab4c..e491fd26daa1984123553eae194d927ee2706bfd 100644 (file)
--- a/Doc/library/stdtypes.rst
+++ b/Doc/library/stdtypes.rst
@@ -3828,7 +3828,7 @@ The constructors for both classes work the same:
 
    .. describe:: len(s)
 
-      Return the cardinality of set *s*.
+      Return the number of elements in set *s* (cardinality of *s*).
 
    .. describe:: x in s