1) Anatomical cavities 2) Bone depressions 
• (pl. ) of Fossa
The pleural of fossa. ... (05 Mar 2000) ... 
(Latin) canals or ditches; the Romans greatly relied upon canals and undertook large projects to dig canals in provinces such as Britain and Egypt; fossae are also ditches dug around a Roman camp of a depth of approximately five feet to protect against an invading enemy.
ditches Although the typical Roman military ditch had a regular V-like profile, termed by Hyginus a fossa fastigata, there were other types of ditch employed. Ditches with a W-like profile may either be of the cippus type, or represent subsequent recuttings of a normal V-profile ditch on a slightly different line. The fossa punica is another well-k...