or **FOSSE**, in *Fortification*, a ditch or moat. The word in French is formed from the participle *fosseum*, of the Latin verb *fodio*, I dig.

Foss, *Fossa*, in *Anatomy*, a kind of cavity in a bone, with a large aperture, but no exit or perforation. When the aperture is very narrow it is called a *sinus*.

Foss is particularly used for the cavity or indenture in the back part of the neck.