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Related to umbos: Umbo of tympanic membrane


n. pl. um·bo·nes (ŭm-bō′nēz) or um·bos
1. The boss or knob at the center of a shield.
a. Biology A knoblike protuberance arising from a surface, as the prominence near the hinge of a bivalve shell or the raised area in the center of the cap of a mushroom.
b. Anatomy A small projection at the center of the outer surface of the eardrum.

[Latin umbō, umbōn-; see nobh- in Indo-European roots.]

um′bo·nal (ŭm′bə-nəl, ŭm-bō′nəl) adj.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.


n, pl umbones (ʌmˈbəʊniːz) or umbos
1. (Botany) a small hump projecting from the centre of the cap in certain mushrooms
2. (Zoology) a hooked prominence occurring at the apex of each half of the shell of a bivalve mollusc
3. (Anatomy) anatomy the slightly convex area at the centre of the outer surface of the eardrum, where the malleus is attached on the internal surface
4. (Arms & Armour (excluding Firearms)) a large projecting central boss on a shield, esp on a Saxon shield
[C18: from Latin: boss of a shield, projecting piece]
umbonate, umbonal, umbonic adj
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014


(ˈʌm boʊ)

n., pl. um•bo•nes (ʌmˈboʊ niz) um•bos.
1. a boss on a shield.
2. any similar boss or protuberance.
3. the beak of a bivalve shell; the protuberance of each valve above the hinge.
4. the raised area on the inner surface of the tympanic membrane, where the malleus is attached.
[1715–25; < Latin umbō; akin to umbilīcus (see umbilicus)]
um′bo•nal (-bə nl) adj.
um′bo•nate (-nɪt, -ˌneɪt) adj.
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.umbo - a slight rounded elevation where the malleus attaches to the eardrumumbo - a slight rounded elevation where the malleus attaches to the eardrum
eardrum, myringa, tympanic membrane, tympanum - the membrane in the ear that vibrates to sound
convex shape, convexity - a shape that curves or bulges outward
Based on WordNet 3.0, Farlex clipart collection. © 2003-2012 Princeton University, Farlex Inc.
References in classic literature ?
On a day, so far back that there was no way of estimating its distance, one, Somo, son of Loti, who was the chief of the island fortress of Umbo, had quarrelled with his father and fled from his wrath along with a dozen canoe-loads of young men.
(2) The four species have different shell shapes, including prominence of umbos, shapes of anterior and posterior ends, rotation of the longitudinal axis, and shell length-height ratio.
Teliospores ellipsoid, rounded at both ends, dark brown, slightly constricted at the septa, 18-21 x 26-32 um; wall 1-1.5 um thick, smooth; germ pore 1 per cell, mostly apical in the distal cell and near the pedicel or at the septum in the proximal cell, hyaline umbos over the germ pores; apex not thickened; pedicel short, hyaline, not persistent, 3-13 um long.
Concha pequena, delgada, inflada, con borde anterior redondeado y el lado posterior prolongado para formar un largo rostrum cuyo borde dorsal es ligeramente concavo y bicarinado en cada valva, el espacio entre las carinas presenta, cuerdas concentricas; el area umbonal lleva varias cuerdas concentricas notorias y en el resto del disco hay finas estrias concentricas; charnela taxodonta con 18 dientes anteriores y 30 posteriores; el ligamento se inserta oblicuamente en suaves depresiones del condroforo, el cual es una lamina situada bajo los umbos. El periostraco olivaceo cubre la conchilla blanquecina; interior blanco nacarado algo translucido y los bordes de las valvas lisos.
According to Bonetto (1967), the genus Anodontites consists of a group of species in whose shell shape varies from oval to eliptical, with subsolid valves (in spite of being fragile for the great development of the prismatic nacreous layer), umbos a little prominent and with no sculptures.