diff --git a/doc/ref/spec.md b/doc/ref/spec.md
index 9153fa3..6292616 100644
--- a/doc/ref/spec.md
+++ b/doc/ref/spec.md
@@ -1624,7 +1624,7 @@
 - `s =~ r` is true if `s` matches the regular expression `r`.
 - `s !~ r` is true if `s` does not match regular expression `r`.
 <!-- TODO: Implementations should adopt an algorithm that runs in linear time? -->
-<!-- Consider implementing Level 2 of Unicode regular expresssion. -->
+<!-- Consider implementing Level 2 of Unicode regular expression. -->
 
 ```
 3 < 4       // true