or Fossa, in anatomy, a kind of cavity in a bone, with a large aperture, but no exit or perforation.

fortification, a hollow place, commonly full of water, lying between the scarp and counter-scarp, below the rampart; and turning round a fortified place or a post, that is to be defended. See Moat.

Foss-Ways, one of the four principal highways of England, that anciently led through the kingdom, supposed to be made by the Romans, having a ditch upon one side thereof.