Run together version of the words, "what's that?"

(Can be used to achieve a childish effect, as it is often said by young children who cannot properly form words yet.)

Sometimes shortened further, simply to, "w'sat?" or "sat?"
John: I just bought a Docform 2000!!
Ian: A Docform 2000? Whassat?
by .Louieee July 29, 2009
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