ŏnŏmătŏpoeïa, ae, f., = ὀνοματοποιΐα,
the forming of a word to resemble in sound the thing it signifies , onomatopée , Charis. p. 245 P.
·noun The formation of words in imitation of sounds; a figure of speech in which the sound of a word...
Webster's Dictionary of the English Language