diff --git a/README.md b/README.md
index 42ded74..79499dc 100644
--- a/README.md
+++ b/README.md
@@ -200,7 +200,7 @@ String
 <str>  = <str>.replace(old_str, new_str)
 <list> = <str>.split(sep=None, maxsplit=-1)  # Splits on whitespaces by default.
 <str>  = <str>.strip('<chars>')
-<str>  = <str>.join(<list>)
+<str>  = <str>.join(<list>)       # Joins elements with separator.
 <bool> = <str>.startswith(<str>)  # Pass tuple of strings for multiple options.
 <bool> = <str>.endswith(<str>)    # Pass tuple of strings for multiple options.
 <bool> = <str>.isnumeric()        # True if str contains only numeric characters.