#5486: typos.
diff --git a/Doc/library/re.rst b/Doc/library/re.rst
index ed50ddb..6e499a0 100644
--- a/Doc/library/re.rst
+++ b/Doc/library/re.rst
@@ -16,7 +16,7 @@
Both patterns and strings to be searched can be Unicode strings as well as
8-bit strings. However, Unicode strings and 8-bit strings cannot be mixed:
that is, you cannot match an Unicode string with a byte pattern or
-vice-versa; similarly, when asking for a substition, the replacement
+vice-versa; similarly, when asking for a substitution, the replacement
string must be of the same type as both the pattern and the search string.
Regular expressions use the backslash character (``'\'``) to indicate