The oversized belly of an individual who appears to be thin in regular clothes, yet has a disproportionably large tummy.

Source: Quatto was introduced in the 1990's movie Total Recall. Quatto lived in a man's stomach while visiting Mars and became famous for the phrase, "Quaid, Release your mind". Unfortunately, Quatto's acting career came to a screeching halt when he was shot in the head.
Seriously you stink Russ, stop feeding quatto buffalo wings?

Nice shirt Todd, but I didn't know we were bringing quatto to the party.

Let's stop here, Quatto's really hungry
by Justin James August 14, 2005
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noun. a turd that becomes stuck to a wall or other object after being thrown or catapulted through the air.
I was sweeping out the hangar the other day, and spotted a big, nasty quatto.
by Mr. North April 27, 2006
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