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Related to umbo: gumbo, Umbo of tympanic membrane, Umbro


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.


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


(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.
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
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.
Bivalve size was measured by the perpendicular axes of height, from umbo to distal tip, and length, the longest axis from anterior to posterior ends.
Ventral valve lateral profile anterior to the umbo gently convex with maximum height at the umbonal region.
Modern art's new muse was the shop window dummy, celebrated in photographs by Umbo (Fig.
As they converge at the umbo of each Pectunculus shell, the hatching is redoubled to emphasize the somewhat darker nub where the valves are joined.
The lesion had extended from slightly below the level of the pyramidal process to just anterior to the cochleariform process; it did not extend below the level of the umbo.
The rounded end near the umbo is the anterior and is the thickest part of the shell while the posterior end is the thinner area.
Studies were based upon external shell features, including shell, length, thickness and width, examining features such as pedicle valve, brachial valve, hinge line, foramen development or non-development, delthyrium (notch) status, shell shape, umbo (posterior extremity) shape, commissure line shape, existence or non-existence of fold and sulcus, their development and type of decoration.
The police acted after the protesters pelted them with stones in the town of Kom Umbo, the source said.
If the Pentamerus oblongus were still there, the tip, or umbo, of the fossilized shell would protrude from the rock.
They found the umbo - where the eardrum connects to the hammer or malleus - produced the greatest sound vibration, particularly if the incus or anvil bone first was removed surgically.
Stuart Umbo, Content Developer at the Science Museum, said: "Robotville explores how robots will become an inherent part of life in the future.