Use Evolution... MAN... it is SWEET! Assuming *NIX... and other X type stuff...
On that NIT...
Actually it is "X - a portable, network-transparent window system" ... as the follow-on from "W, - THE network-transparent window system"
as the myth/legend/story/fact/manpage states...
X
X Window System
X Version 11
X Window System, Version 11
X11
Sorry, but I just couldna let that GO anymore!