noun (n)

• a concavity in a surface (especially an anatomical depression)(noun.shape)

  Synonym:
  pit
  

  source: wordnet30
• monotypic genus of Madagascar civets closely related to palm civets(noun.animal)

  Synonym:
  genus fossa
  

  source: wordnet30
• largest carnivore of Madagascar; intermediate in some respects between cats and civets(noun.animal)

  Synonym:
  cryptoprocta ferox, fossa cat
  

  source: wordnet30
• A pit, groove, cavity, or depression, of greater or less depth; as, the temporal fossa on the side of the skull; the nasal fossæ containing the nostrils in most birds.(noun)

  source: webster1913