1. n. The alt shift key on an IBM PC or
clone keyboard; see bucky bits, sense 2 (though typical
PC usage does not simply set the 0200 bit). 2. n. The `option'
key on a Macintosh; use of this term usually reveals that the
speaker hacked PCs before coming to the Mac (see also feature key, which is sometimes incorrectly called `alt').
3. n.,obs. [PDP-10; often capitalized to ALT] Alternate name
for the ASCII ESC character (ASCII 0011011), after the keycap
labeling on some older terminals; also `altmode' (/awlt'mohd/).
This character was almost never pronounced `escape' on an ITS
system, in TECO, or under TOPS-10 -- always alt, as in "Type
alt alt to end a TECO command" or "alt-U onto the system" (for
"log onto the [ITS] system"). This usage probably arose because
alt is more convenient to say than `escape', especially when
followed by another alt or a character (or another alt and a
character, for that matter). 4. The alt hierarchy on Usenet,
the tree of newsgroups created by users without a formal vote and
approval procedure. There is a myth, not entirely implausible,
that alt is acronymic for "anarchists, lunatics, and
terrorists"; but in fact it is simply short for "alternative".
< ALPHA PARTICLES | A^ | ALT BIT >