Definition of arrises:
(n) :
A sharp edge or ridge formed by the intersection of two surfaces
(n) :
(architecture) A sharp edge or ridge formed by the intersection of two curved surfaces
(n) :
(archaeology) A ridge formed on the surface of flaked stone, such as an arrowhead or hand axe, as the result of the intersection of two or more flake removals.
(n) :
Alternative spelling of aris [(Cockney rhyming slang) arse]