Source : Webster's Revised Unabridged Dictionary (1913)

Onomatopoetic \On`o*mat`o*po*et"ic\, a.
   Of or pertaining to onomatop[oe]ia; characterized by
   onomatop[oe]ia; imitative; as, an onomatopoetic writer or
   word. --Earle.

Source : WordNet®

onomatopoetic
     adj 1: of or relating to or characterized by onomatopoeia [syn: {onomatopoeic}]
     2: (of words) formed in imitation of a natural sound;
        "onomatopoeic words are imitative of noises"; "it was
        independently developed in more than one place as an
        onomatopoetic term"- Harry Hoijer [syn: {echoic}, {imitative},
         {onomatopoeic}, {onomatopoeical}] [ant: {nonechoic}]