Is UNIX an acronym? What does it stand for?

3 Answers 3


First, there was UNICS for Uniplexed Information Computing System. Then the name changed for UNIX. Same pronunciation.

  • 3
    From wikipedia: In the 1960s, Massachusetts Institute of Technology, AT&T Bell Labs, and General Electric developed an experimental operating system called Multics for the GE-645 mainframe.[2] Multics was highly innovative, but had many problems.. In the 1970s Brian Kernighan coined the project name Unics as a play on Multics, (Multiplexing Information and Computer Services). Unics could eventually support multiple simultaneous users, and it was renamed Unix.
    – tmow
    Commented Jan 14, 2011 at 8:08
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    Multics may have initially been experimental, but it lasted quite a while. I learnt to program in FORTRAN 77 on a Honeywell Multics machine in 1987.
    – onestop
    Commented Jan 14, 2011 at 11:35

Despite often being written in all caps, UNIX is not an acronym, therefore it doesn't have a full expansion. The name is a play on Multics which was an acronym (Multiplexed Information and Computing Service). That was an other early operating system around at the time of Unix creation.

Edit: As Marc stated it was originaly called Unics but once it could support multiple users it was renamed Unix which is not an acronym.

  • I believe the usual spelling was U<smallcaps>nix</smallcaps>, but of course you can't do that in plain ASCII, nor do it easily in many word processors, so the smallcaps distinction is regularly ignored. Commented Jan 15, 2011 at 18:51
  • I believe the 'x' was something of a misspelling or abbreviation at first.
    – vonbrand
    Commented Jan 23, 2013 at 14:52
  • Unix, originally Unics.
  • Peter Gabriel Neumann named it UNICS (UNiplexed Infomation and Computing Service) as a pun on the multi-user MULTICS(MULTiplexed Information and Computing Service) system.
  • Peter Gabriel Neumann (born 1932) is a computer-science researcher who worked on the Multics operating system in the 1960s.
  • Multics was a mainframe time-sharing operating system that was developed in the 1963-1969 period through the collaboration of the Massachusetts Institute of Technology (MIT), General Electric (GE), and Bell Labs.

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