The Collaborative International Dictionary of English v.0.48:

Archimedes \Ar`chi*me"des\, n. (Paleon.)
   An extinct genus of Bryzoa characteristic of the
   subcarboniferous rocks. Its form is that of a screw.
   [1913 Webster]

Jargon File (4.4.4, 14 Aug 2003):

Archimedes


   The world's first RISC microcomputer, available only in the British
   Commonwealth and europe. Built in 1987 in Great Britain by Acorn
   Computers, it was legendary for its use of the ARM-2 microprocessor
as
   a CPU. Many a novice hacker in the Commonwealth first learnt his or
   her skills on the Archimedes, since it was specifically designed for
   use in schools and educational institutions. Owners of Archimedes
   machines are often still treated with awe and reverence. Familiarly,
   "archi".