diff --git a/Doc/documenting/markup.rst b/Doc/documenting/markup.rst
index 618e7da..690d056 100644
--- a/Doc/documenting/markup.rst
+++ b/Doc/documenting/markup.rst
@@ -221,6 +221,11 @@
 
          Run a module as a script.
 
+.. describe:: envvar
+
+   Describes an environment variable that Python uses or defines.
+
+
 There is also a generic version of these directives:
 
 .. describe:: describe