Xanax
         n 1: an antianxiety agent (trade name Xanax) of the
               benzodiazepine class [syn: {alprazolam}, {Xanax}]

English Dictionary: Xmas	by the DICT Development Group
From WordNet (r) 3.0 (2006) [wn]:
Xmas n a Christian holiday celebrating the birth of Christ; a quarter day in England, Wales, and Ireland Synonym(s): Christmas, Christmas Day, Xmas, Dec 25
From The Free On-line Dictionary of Computing (15Feb98) [foldoc]:
Xemacs          (Originally "Lucid Emacs") A text editor for the       {X Window System}, based on {GNU} {Emacs} version 19, produced       by a collaboration of {Lucid, Inc.}, {SunPro} (a division of       {Sun Microsystems, Inc.}), and the {University of Illinois}.          Lucid chose to build part of {Energize}, their {C}/{C++}       development environment on top of GNU Emacs.   Though their       product is commercial, the work on GNU Emacs is {free       software}, and is useful without having to purchase the       product.   They needed a version of Emacs with mouse-sensitive       regions, multiple fonts, the ability to mark sections of a       buffer as read-only, the ability to detect which parts of a       buffer has been modified, and many other features.          The existing version of {Epoch} was not sufficient; it did not       allow arbitrary {pixmaps} and {icons} in buffers, "undo" did       not restore changes to regions, regions did not overlap and       merge their attributes.   Lucid spent some time in 1990 working       on Epoch but later decided that their efforts would be better       spent improving Emacs 19 instead.          Lucid did not have time to get their changes accepted by the       {FSF} so they released Lucid Emacs as a forked branch of       Emacs.   Roughly a year after Lucid Emacs 19.0 was released, a       beta version of the FSF branch of Emacs 19 was released.       Lucid continued to develop and support Lucid Emacs, merging in       bug fixes and new features from the FSF branch as appropriate.          A compatibility package was planned to allow Epoch 4 code to       run in Lemacs with little or no change.   (As of 19.8, Lucid       Emacs ran a descendant of the Epoch redisplay engine.)          [Update?]          (2000-05-16)
From The Free On-line Dictionary of Computing (15Feb98) [foldoc]:
XENIX          A commercial version of {Unix} for       {microprocessor}-based computers, released by {Microsoft} in       1980. In 1992, {SCO} became Microsoft's co-development partner       and the alternate source for the product.          (1999-12-07)
From The Free On-line Dictionary of Computing (15Feb98) [foldoc]:
XMS          {Extended Memory Specification}.          (1996-01-10)
From The Free On-line Dictionary of Computing (15Feb98) [foldoc]:
XNS          {Xerox Network System} or Xerox Network Services.          [Which?]