diff --git a/USES b/USES
index 8c002070..6d5f4c85 100644
--- a/USES
+++ b/USES
@@ -7,6 +7,7 @@ gawk                   GNU awk.
 gnumake                GNU makefile.
 mpv                    A free, open source, and cross-platform media player.
 openlisp               ISLISP ISO/IEC 13816 Lisp interpreter and compiler
+s-nail                 BSD Mail/POSIX mailx: send and receive Internet mail
 sqlite                 Embbedable SQL engine.
 st                     Simple Terminal.
 tcc                    Tiny CC which compiles itself.