um·bo [ úmbō ](pluralum·bo·nes [ um bṓneez ] or um·bos)
noun
Definition:
1. bump on plant or animal part: a small protuberance on a plant or animal part, e.g. the hump on the caps of some mushrooms, or the bump just above the hinge of a bivalve shell
2. small hollow in eardrum: a small hollow in the center of the outer surface of the eardrum, at the point where the malleus joins it on the inside
3. knob on shield: a knob at the center of a round shield, especially a Saxon shield