diff --git a/regexp.py b/regexp.py
--- a/regexp.py
+++ b/regexp.py
@@ -11,7 +11,7 @@ class ParsingError(Exception):
 
 
 class Token:
-	"""Abstract base class representing a single item of a regular expressions."""
+	"""Abstract base class representing a single item of a regular expression."""
 	# is the Token mandatory, or can it be omitted
 	is_skippable = False