um|bo

um|bo «UHM boh», noun, plural um|bo|nes «uhm BOH neez», um|bos.

1. a projection or knob, often pointed, near or at the center of a shield.

2. any elevation resembling this, as in the eardrum.

3. Zoology. the oldest and most protuberant portion of a bivalve mollusk shell, located near the hinge.

╂[< Latin umbō, -ōnis boss of a shield, knob, projection, related to umbilīcus navel]