Illustration of fossa
- 2fossa
fossa
1 of 2noun (1)
fos·sa ˈfä-sə 
plural fossae ˈfä-ˌsē
-ˌsī
: an anatomical pit, groove, or depression
fossa
2 of 2noun (2)
: a slender, long-tailed, carnivorous mammal (Cryptoprocta ferox of the family Eupleridae) of Madagascar that has retractile claws, usually reddish-brown or sometimes black, short, thick fur, and anal scent glands
The fossa evolved on the catless island of Madagascar, where it became the ecological equivalent of a cat. With nothing else around to fill the role, the fossa became a sort of mini-leopard, hunting lemurs and other small animals in the forest at night.
Fiona Sunquist
Fiona Sunquist 
Word History
Etymology
Noun (1)
borrowed from Medieval Latin, going back to Latin, "ditch, trench," noun derivative from feminine of fossus, past participle of fodere "to jab, dig" — more at fossil entry 1
Noun (2)
borrowed from French, borrowed from Malagasy fosa
First Known Use
Noun (1)
1733, in the meaning defined above
Noun (2)
1838, in the meaning defined above
Medical Definition
fossa
noun
fos·sa ˈfäs-ə
plural fossae -ˌē -ˌī
-ˌī : an anatomical pit, groove, or depression
the temporal fossa of the skull
the fossa in the liver for the gallbladder