Source : Webster's Revised Unabridged Dictionary (1913)

Parser \Pars"er\, n.
   One who parses.

Source : WordNet®

parser
     n : a computer program that divides code up into functional
         components; "compilers must parse source code in order to
         translate it into object code"

Source : Free On-Line Dictionary of Computing

parser
     
         An {algorithm} or program to determine the
        syntactic structure of a sentence or string of symbols in some
        language.  A parser normally takes as input a sequence of
        {tokens} output by a {lexical analyser}.  It may produce some
        kind of {abstract syntax tree} as output.  One of the best
        known {parser generators} is {yacc}.
     
        (1997-07-21)