umbo

[ uhm-boh ]

/ ˈʌm boʊ /

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noun, plural um·bo·nes

[uhm-boh-neez], /ʌmˈboʊ niz/, um·bos.

a boss on a shield, as one at the center of a circular shield.

any similar boss or protuberance.

Zoology. the beak of a bivalve shell; the protuberance of each valve above the hinge.

Anatomy. 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.

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Origin of umbo

1715–25; <Latin umbō boss (of a shield), knob, projecting part; akin to umbilīcus (see umbilicus)

Words nearby umbo

umbilication, umbilicus, umbiliform, umble pie, umbles, umbo, umbonal, umbonate, umbra, umbrage, umbrageous

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2021

How to use umbo in a sentence

One species (C. discors) is pale green, with radiating lines from umbo to margin.
The Sea Shore|William S. Furneaux
The hand was protected by a hollow conical boss or umbo, fixed to the wood by its brim, but projecting considerably.
Beowulf|R. W. Chambers
It is a light pelagic form, with paper-like plates and angularly bent carina, with a prominent umbo.
Journal of Entomology and Zoology: Volume 6, Number 4, December 1914|Various
One is in the Spanish-Moorish style and of a convex shape, with iron bordering and umbo, and a lining of yellow brocade.
The Arts and Crafts of Older Spain, Volume I (of 3)|Leonard Williams

The paracentesis knife is inserted boldly through the membrane a little behind and above the umbo.
A System of Operative Surgery, Volume IV (of 4)|Various

British Dictionary definitions for umbo

umbo

/ (ˈʌmbəʊ) /

noun plural umbones (ʌmˈbəʊniːz) or umbos

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

anatomy 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

Derived forms of umbo

umbonate (ˈʌmbənɪt, -ˌneɪt), umbonal (ˈʌmbənəl) or umbonic (ʌmˈbɒnɪk), adjective

Word Origin for umbo

C18: from Latin: boss of a shield, projecting piece

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Medical definitions for umbo

umbo

[ ŭm′bō ]

n. pl. um•bos

A small anatomical projection on a surface, such as that on the inner surface of the tympanic membrane at the end of the manubrium of the malleus, corresponding to the most depressed point of the membrane.

Other words from umbo

um′bo•nal (ŭm′bə-nəl, ŭm-bō′nəl) null adj.