bpo-39233: Update positional-only section in the glossary (GH-17874)



https://bugs.python.org/issue39233
diff --git a/Doc/glossary.rst b/Doc/glossary.rst
index 9ce0357..6189cb0 100644
--- a/Doc/glossary.rst
+++ b/Doc/glossary.rst
@@ -824,9 +824,11 @@
       .. _positional-only_parameter:
 
       * :dfn:`positional-only`: specifies an argument that can be supplied only
-        by position.  Python has no syntax for defining positional-only
-        parameters.  However, some built-in functions have positional-only
-        parameters (e.g. :func:`abs`).
+        by position. Positional-only parameters can be defined by including a
+        ``/`` character in the parameter list of the function definition after
+        them, for example *posonly1* and *posonly2* in the following::
+
+           def func(posonly1, posonly2, /, positional_or_keyword): ...
 
       .. _keyword-only_parameter: