a b c d e f g h i j k l m n o p q r s t u v w x y zx, x client, x consortium, x image extension, x protocol, x server, x terminal, x window system, x-1, x-designer, x-scm, x-windows, x.12, x.208, x.209, x.21, x.214, x.215, x.216, x.217, x.219, x.224, x.225, x.226, x.227, x.229, x.25, x.28, x.29, x.3, x.400, x.409, x.500, x.680, x.75, x.desktop, x/open, x/open portability guide, x/open system interface, x11r4, x11r5, x11r6, x2, x3j16, x3t10, x86, x86 processor socket, xa, xaw, xbase, xbeeb, xbm, xc, xcoral, xdbx, xdl, xdr, xds 530, xds 940, xdsl, xemacs, xenix, xeon, xerox corporation, xerox data systems model 530, xerox data systems model 940, xerox network services, xerox network system, xerox parc, xerox star, xfree86 project, inc., xfun, xga, xga-2, xhtml, xi, xie, xilinx netlist format, xilinx, inc., xlib, xlisp, xls, xml, xml schema, xml template pages, xml user-interface language, xmm, xmodem, xmodem-1k, xmosaic, xms, xnf, xnf2ver, xns, xoff, xon, xon/xoff, xopen, xor, xpc, xpercase, xpg, xpg3, xpl, xpm, xpop, xpress transport protocol, xref, xremote, xrn, xsb, xscheme, xsd, xsi, xsl, xslt, xt, xt bus architecture, xterm, xti, xtp, xtp forum, xtran, xui, xul, xv++, xvga, xview, xvt, xwip, xxgdb, xxx, xy-pic, xyzzy