Onomatopoeia
onomatopoeia
(ŏn'əmăt'əpē`ə) [Gr.,=word-making], in
language, the representation of a sound by an imitation
thereof; e.g., the cat
mews.
Poets often convey the
meaning of a verse through its very sound.
http://columbia.thefreedictionary.com/Onomonopiea