umbo

American  

[uhm-boh] / ˈʌm boʊ /

noun

plural

umbones, umbos

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

2. any similar boss or protuberance.

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

4. Anatomy. the depressed area on the outer surface of the tympanic membrane.

5. a blunt or rounded protuberance arising from a surface, as on a pine cone scale.

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umbo British  

/ ˈʌmbənɪt, ʌmˈbɒnɪk, -ˌneɪt, ˈʌmbəʊ, ˈʌmbənəl /

noun

1. a small hump projecting from the centre of the cap in certain mushrooms

2. a hooked prominence occurring at the apex of each half of the shell of a bivalve mollusc

3. 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. a large projecting central boss on a shield, esp on a Saxon shield

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Other Word Forms

• umbonate
  adjective

Etymology

Origin of umbo

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

Example Sentences

P. 1-1.5 cm. exp. disc depr. round pale small umbo, rufous or yellowish; g. crowded, white; s. 3-5 cm. slender, tough, glabrous, tinged fuscous, base rooting, fibrillose; sp.

From European Fungus Flora: Agaricaceae by Massee, George

P. 2-4 cm. conical, exp. rufous bay, prominent umbo darker; g. adnexed; s. 3-5 cm. equal, somewhat curved, violet above; sp. ——. var. argyropus.

From European Fungus Flora: Agaricaceae by Massee, George

Brachiopoda, with the pedicle-opening, confined in later life to the ventral valve, and placed at the umbo or beneath it.

From Encyclopaedia Britannica, 11th Edition, Volume 4, Slice 3 "Borgia, Lucrezia" to "Bradford, John" by Various

P. tough, exp. subfibrillose, umbo evanescent, greyish white, shining, floccosely scaly; g. shining white then dingy; s. long, striate, abruptly rooting. platyphylla, Fr.

From European Fungus Flora: Agaricaceae by Massee, George

P. convex, subdepr. with a slight umbo, whitish yellow; g. crowded, pale cinnamon; s. reddish. macilenta, Fr.

From European Fungus Flora: Agaricaceae by Massee, George