diff --git a/src/encoding/json/encode.go b/src/encoding/json/encode.go
index 02522f088a..d53e862d73 100644
--- a/src/encoding/json/encode.go
+++ b/src/encoding/json/encode.go
@@ -72,8 +72,8 @@ import (
 //
 // The "omitempty" option specifies that the field should be omitted
 // from the encoding if the field has an empty value, defined as
-// false, 0, a nil pointer, a nil interface value, and any empty array,
-// slice, map, or string.
+// false, 0, a nil pointer, a nil interface value, and any array,
+// slice, map, or string of length zero.
 //
 // As a special case, if the field tag is "-", the field is always omitted.
 // Note that a field with name "-" can still be generated using the tag "-,".