diff --git a/lisp/subr.el b/lisp/subr.el
index cfce5b18c55..15662162798 100644
--- a/lisp/subr.el
+++ b/lisp/subr.el
@@ -5435,7 +5435,7 @@ and replace a sub-expression, e.g.
       (apply #'concat (nreverse matches)))))
 
 (defsubst string-equal-ignore-case (string1 string2)
-  "Like `string-equal', but case-insensitive.
+  "Compare STRING1 and STRING2 case-insensitively.
 Upper-case and lower-case letters are treated as equal.
 Unibyte strings are converted to multibyte for comparison."
   (declare (pure t) (side-effect-free t))