UNIX
: /yoo'niks/ [In the authors' words, "A weak pun on
Multics"] n. (also `Unix') An interactive time-sharing system
invented in 1969 by Ken Thompson after Bell Labs left the Multics
project, originally so he could play games on his scavenged PDP-7.
Dennis Ritchie, the inventor of C, is considered a co-author of the
system. The turning point in UNIX's history came when it was
reimplemented almost entirely in C during 1972--1974, making it the
first source-portable OS. UNIX subsequently underwent mutations
and expansions at the hands of many different people, resulting in
a uniquely flexible and developer-friendly environment. By 1991,
UNIX had become the most widely used multiuser general-purpose
operating system in the world. Many people consider this the most
important victory yet of hackerdom over industry opposition (but
see UNIX weenie and UNIX conspiracy for an opposing point
of view). See Version 7, BSD, USG UNIX.