Definition of Posix in English:

Posix

(also POSIX)

Pronunciation /ˈpäsiks/ /ˈpɑsɪks/

noun

Computing
  • A set of formal descriptions that provide a standard for the design of operating systems, especially ones which are compatible with Unix.

    ‘If the community can sort out some issues between Linux and Posix, the user community may choose to adopt those interfaces, but they will vote with their feet not in a consortium.’
    • ‘QNX is also Posix compliant, so there is lots of software that almost works under it.’
    • ‘Carrier-grade features to be added include support for Posix compliant threading, diskless blade systems, improved systems responsiveness, and advanced debugging and systems analysis.’
    • ‘‘You can implement Posix today with the limited swap instructions that are there today,’ he said.’
    • ‘I still think that something like POSIX capabilities is important, but I'm not so sure anymore that Posix capabilities is the right way to go about solving the problem.’

Origin

1980s from the initial letters of portable operating system + -ix suggested by Unix.