Source : Webster's Revised Unabridged Dictionary (1913)

Clarion \Clar"i*on\, n. [OE. clarioun, OF. clarion, F. clairon,
   LL. clario, claro; so called from its clear tone, fr. L.
   clarus clear. See {Clear}.]
   A kind of trumpet, whose note is clear and shrill.

         He sounds his imperial clarion along the whole line of
         battle.                                  --E. Everett.

Source : WordNet®

clarion
     adj : loud and clear; "a clarion call"
     n : a medieval brass instrument with a clear shrill tone
     v 1: blow the clarion
     2: proclaim on, or as if on, a clarion

Source : Free On-Line Dictionary of Computing

Clarion
     
         A {fourth generation language} for {MS-DOS}.
     
        [Details?]
     
        (1994-11-09)