Portable Operating System Interface

Portable Operating System Interface

(operating system, standard)(POSIX) A set of IEEE standardsdesigned to provide application portability between Unixvariants. IEEE 1003.1 defines a Unix-like operating systeminterface, IEEE 1003.2 defines the shell and utilities andIEEE 1003.4 defines real-time extensions.

["More UNIX For Dummies", ISBN: 1-56884-361-5] says it standsfor "Portable Operating System Interface with an X thrown into make it sound cooler."