umbo Definition

umbo
noun umbones, umbos

1. The central boss of a shield.
2. zool.
The protuberant oldest part of a bivalve shell.
3. bot.
A knob or protuberance on the cap of certain fungi.
4. anatomy.
A projection on the inner surface of the eardrum where the malleus is attached.

Derivative: umbonal
adj

Derivative: umbonate
adj

Etymology: 18c: Latin, meaning ‘the boss of a ‘shield', ‘knob' or ‘protuberance'.