umbo

noun

um·​bo ˈəm-(ˌ)bō 

plural umbones ˌəm-ˈbō-(ˌ)nēz  or umbos

1

: the boss of a shield

2

: a rounded elevation: such as

a

: an inward projection of the tympanic membrane of the ear

b

: one of the lateral prominences just above the hinge of a bivalve shell

umbonal

ˈəm-bə-nᵊl  ˌəm-ˈbō- 

adjective

umbonate

ˈəm-bə-ˌnāt  ˌəm-ˈbō-nət 

adjective

Illustration of umbo

• U umbo 1

Word History

Etymology

Latin; akin to Latin umbilicus — more at navel

First Known Use

1721, in the meaning defined at sense 1

Medical Definition

umbo

noun

um·​bo ˈəm-(ˌ)bō 

plural umbones ˌəm-ˈbō-(ˌ)nēz  or umbos

: an elevation in the tympanic membrane of the ear