Despite the previous definition, (which also happens to be spelled incorrectly - ie: Foosa), this animal does indeed exist. It is NOT however a slang term used to refer to hyenas, as previously stated. Many people have recently been introduced to this animal by the movie "Madagascar." The Fossa(Cryptoprocta ferox)is the largest carnivore endemic to the island of Madagascar, and is a catlike member of the civet family. It usually hunts alone and commonly feeds on birds and lemurs but also preys on livestock. This is precisely why the lemur characters in the movie were always afriad of "The Fossa!"
For an expanded definition and pictures of the Fossa please see Encyclopedia Brittanica online.

"We thank you with enormous gratitude for chasing away the fossa (foo-sah).
"
- Julian
"Madagascar"
by CrrrlyGirl March 18, 2008
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A deep groove on a flat surface that magically attracts readas to be stuck in them. Commonly found near Via Appia.
Cave fossam!
Reada in fossa est.
Reada adhuc in fossa est.
by Yes, I am a Mike January 30, 2017
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something that is built up to be great but is utterly disappointing. The Fossa is a meat-eating mammal from the island of Madagascar and was built up at Marwell Zoo to be the most 'mysterious creature' about. It was rubbish.
Will: The new Wembely stadium will be ready soon
Megan: I hope its not a fossa
by Will Satterthwaite April 16, 2006
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aka "sternal notch." a great place to deposit semen when you give a girl a "pearl necklace."
i filled that bitch's pearl necklace fossa the other night
by sudmat May 11, 2009
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A kind of ditch that magically attracts raeda to be stuck in it.
Raeda in fossa est.
Cave fossam!
by Flawia December 24, 2016
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