http://onomatopoetically.com/I have a (temporary) new favorite word:
If you go to merriam-webster.com it has a pronunciation clip, cracks me up.
But you know what's even better? The definition.
"The naming of a thing or action by a vocal imitation of the sound associated with it (as buzz, hiss."
Such a word for such a definition.
You know what else rocks? There's a whole website devoted to "The naming of a thing by a vocal imitation of the sound associated with it."
Go on, I dare you to use it in a sentence some time today.