The Jargon File (version 4.4.7, 29 Dec 2003):

Wintel
 n.

    Microsoft Windows plus Intel ? the tacit alliance that dominated desktop
    computing in the 1990s. After 1999 it began to break up under pressure from
    Linux; see Lintel.


The Free On-line Dictionary of Computing (30 December 2018):

wintel

    A term describing any computer
   platform consisting of some version of Microsoft Windows
   running on an Intel 80x86 processor or compatible.

   Despite the dominance of the wintel platform, in its many
   forms, from MS-DOS on an Intel 8088 to Windows 2000 on a
   Pentium II Xeon, there are many "non-wintel" platforms in
   use.  These include Acorn, Amiga, Apple, ARM, Atari,
   A\Box, Be, Network Computer, OS/2, PowerPC, Psion,
   Linux and all other Unix systems.

   Convergence International (http://convergence.org/).

   (1999-09-15)