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]

WordNet (r) 3.0 (2006):

Archimedes
    n 1: Greek mathematician and physicist noted for his work in
         hydrostatics and mechanics and geometry (287-212 BC)

The Jargon File (version 4.4.7, 29 Dec 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?.


The Free On-line Dictionary of Computing (30 December 2018):

Archimedes
Acorn Archimedes

    A family of microcomputers produced by Acorn
   Computers, Cambridge, UK.  The Archimedes, launched in June
   1987, was the first RISC based personal computer
   (predating Apple Computer's Power Mac by some seven
   years).  It uses the Advanced RISC Machine (ARM) processor
   and includes Acorn's multitasking operating system and
   graphical user interface, RISC OS on ROM, along with an
   interpreter for Acorn's enhanced BASIC, BASIC V.

   The Archimedes was designed as the successor to Acorn's
   sucessful BBC Microcomputer series and includes some
   backward compatibility and a 6502 emulator.  Several
   utilities are included free on disk (later in ROM) such as a
   text editor, paint and draw programs.  Software emulators
   are also available for the IBM PC as well as add-on Intel
   processor cards.

   There have been several series of Archimedes: A300, A400,
   A3000, A5000, A4000 and RISC PC.

   Usenet FAQ
   (ftp://rtfm.mit.edu/pub/usenet/news.answers/acorn/).
   Archive site list
   (http://cs.vu.nl/~gerben/acorn/acorn-archives.txt).
   HENSA archive (ftp://micros.hensa.ac.uk/).  Stuttgart
   archive (ftp://ftp.uni-stuttgart.de/pub/systems/acorn).

   See also Crisis Software, Warm Silence Software.

   (1998-04-03)