The Collaborative International Dictionary of English v.0.48:

Euclid \Eu"clid\, n.
   A Greek geometer of the 3d century b. c.; also, his treatise
   on geometry, and hence, the principles of geometry, in
   general.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Euclid
    n 1: Greek geometer (3rd century BC)

The Free On-line Dictionary of Computing (19 January 2023):

Euclid
Ottawa Euclid

    (Named after the Greek geometer, fl ca 300 BC.) A
   Pascal descendant for development of verifiable system
   software.  No goto, no side effects, no global
   assignments, no functional arguments, no nested procedures, no
   floats, no enumeration types.  Pointers are treated as
   indices of special arrays called collections.  To prevent
   aliasing, Euclid forbids any overlap in the list of actual
   parameters of a procedure.  Each procedure gives an imports
   list, and the compiler determines the identifiers that are
   implicitly imported.  Iterators.

   Ottawa Euclid is a variant.

   ["Report on the Programming Language Euclid", B.W. Lampson et
   al, SIGPLAN Notices 12(2):1-79, Feb 1977].

   (1998-11-23)