- a boss on a shield, as one at the center of a circular shield.
- any similar boss or protuberance.
- the beak of a bivalve shell; the protuberance of each valve above the hinge.
- the depressed area on the outer surface of the tympanic membrane.
- a blunt or rounded protuberance arising from a surface, as on a pine cone scale.
- a small hump projecting from the centre of the cap in certain mushrooms
- a hooked prominence occurring at the apex of each half of the shell of a bivalve mollusc
- the slightly convex area at the centre of the outer surface of the eardrum, where the malleus is attached on the internal surface
- a large projecting central boss on a shield, esp on a Saxon shield
