fossa

• POS: Noun
• HYPHEN: fos=sa

CIDE DICTIONARY

fossa, n. [L., a ditch. See Fosse.].

 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.  [1913 Webster]

OXFORD DICTIONARY

fossa, n. (pl. fossae) Anat. a shallow depression or cavity.

Etymology

L, = ditch, fem. past part. of fodere dig