A sharp edge or ridge formed by the intersection of two surfaces
A ridge formed on the surface of flaked stone, such as a arrowhead or hand axe, as the result of the intersection of two or more flake removals.
A sharp edge or ridge formed by the intersection of two curved surfaces
Buttocks, arse.
The triangular area at the peak of an external wall adjacent to, and terminating, two sloped roof surfaces (pitches).