| n. | 1. | (Anat.) A pit, groove, cavity, or depression, of greater or less depth; |
| Noun | 1. | fossa - a concavity in a surface (especially an anatomical depression) Synonyms: pit |
| 2. | Fossa - monotypic genus of Madagascar civets closely related to palm civets Synonyms: genus Fossa | |
| 3. | fossa - largest carnivore of Madagascar; intermediate in some respects between cats and civets Synonyms: Cryptoprocta ferox, fossa cat |