1 of 2

noun (1)

fos·​sa ˈfä-sə How to pronounce fossa (audio)
plural fossae ˈfä-ˌsē How to pronounce fossa (audio)
: an anatomical pit, groove, or depression


2 of 2

noun (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

Illustration of fossa

Illustration of fossa
  • 2fossa

Examples of fossa in a Sentence

Recent Examples on the Web
In life, the carnivore was about the size of a bobcat and probably behaved like a civet or fossa. Riley Black, Smithsonian Magazine, 29 June 2023 If regional anesthesia is used, the anesthetic may be injected in the spine (spinal epidural block) or a shallow bundle of nerves behind the knee called the popliteal fossa. Stuart Hershman, Verywell Health, 27 June 2023 Overall, Poust notes, Diegoaelurus was probably closer in appearance to a civet or a fossa. Riley Black, Smithsonian Magazine, 15 Mar. 2022 By comparison, the far-more-ancient Diegoaelurus was much smaller, about the size of a bobcat, and similar in style to the fossa of Madagascar, a cousin to the mongoose, Poust said. Pam Kragen, San Diego Union-Tribune, 15 Mar. 2022

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'fossa.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


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

Time Traveler
The first known use of fossa was in 1733

Dictionary Entries Near fossa

Cite this Entry

“Fossa.” Dictionary, Merriam-Webster, Accessed 14 Jun. 2024.

Kids Definition


: a slender long-tailed meat-eating mammal of Madagascar that has usually reddish brown short thick fur and is an excellent climber

Medical Definition


fos·​sa ˈfäs-ə How to pronounce fossa (audio)
plural fossae -ˌē How to pronounce fossa (audio) -ˌī How to pronounce fossa (audio)
: an anatomical pit, groove, or depression
the temporal fossa of the skull
the fossa in the liver for the gallbladder
fossate adjective

More from Merriam-Webster on fossa

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!