diff --git a/Doc/reference/lexical_analysis.rst b/Doc/reference/lexical_analysis.rst
index 0ed3d3b9a70..6617c3b4551 100644
--- a/Doc/reference/lexical_analysis.rst
+++ b/Doc/reference/lexical_analysis.rst
@@ -76,7 +76,7 @@ are ignored by the syntax; they are not tokens.
 Encoding declarations
 ---------------------
 
-.. index:: source character set, encodings
+.. index:: source character set, encoding declarations (source file)
 
 If a comment in the first or second line of the Python script matches the
 regular expression ``coding[=:]\s*([-\w.]+)``, this comment is processed as an