diff --git a/cmp/compare.go b/cmp/compare.go
index 83fc5a4..86d0903 100644
--- a/cmp/compare.go
+++ b/cmp/compare.go
@@ -100,8 +100,8 @@ func Equal(x, y interface{}, opts ...Option) bool {
 // same input values and options.
 //
 // The output is displayed as a literal in pseudo-Go syntax.
-// At the start of each line, a "-" prefix indicates an element removed from y,
-// a "+" prefix to indicates an element added to y, and the lack of a prefix
+// At the start of each line, a "-" prefix indicates an element removed from x,
+// a "+" prefix to indicates an element added from y, and the lack of a prefix
 // indicates an element common to both x and y. If possible, the output
 // uses fmt.Stringer.String or error.Error methods to produce more humanly
 // readable outputs. In such cases, the string is prefixed with either an