umbo

American  

[uhm-boh] / ˈʌm boʊ /

noun

• umbones,
  plural
• umbos
  plural

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.

---

umbo British  

/ ˈʌmbəʊ /

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

---

Other Word Forms

Derived Forms

• umbonate
  adjective

Inflected Forms

Nouns

• umbones
  plural
• umbos
  plural

---

Etymology

Origin of umbo

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

---

Example Sentences

See Examples For:

umbo umbones umbos

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 George Massee

P. 4-7 cm. campan. then exp. rufous orange umbo darkest, flesh reddish-ochre; g. adnate, sinuate, bright rusty-red; s. 6-9 cm. pale above, dark below, with darker concentric bands; sp.

From European Fungus Flora: Agaricaceae by George Massee

P. conico-campan. acute umbo blackish, rest reddish brown, striate; g. almost free, pale rose; s. cylindrical, almost translucent, brown, curved. carpophila, Fr.

From European Fungus Flora: Agaricaceae by George Massee

Differs from C. dryophila in umbo, broad gills, and strigosely rooting stem. nitellina, Fr.

From European Fungus Flora: Agaricaceae by George Massee

P. 1.5-2.5 cm. camp. grey, umbo darker, striate to middle, margin upturned and splitting; g. adnexed, grey; s. 2.5-3.5 cm. dry, smooth, paler than p.; sp.

From European Fungus Flora: Agaricaceae by George Massee

On most of the valves there are furrows and ridges diverging from the umbones, and the lines of growth are plainly marked: in the valves of the lower whorl, the umbones are slightly protuberant.

From A Monograph on the Sub-class Cirripedia With Figures of all the Species. by Charles Darwin

Valves 5, approximate: carina extending up between the terga, terminating downwards in an embedded fork, or in an external disc: scuta sub-triangular, with their umbones at the rostral angle.

From A Monograph on the Sub-class Cirripedia With Figures of all the Species. by Charles Darwin

Shell transversely oblong, thick, depressed, within purple; hinge plate thick, truncate, with an obsolete lamellar tooth in each valve; umbones retuse.

From Zoological Illustrations, Volume III or Original Figures and Descriptions of New, Rare, or Interesting Animals by William Swainson

The pointed umbones are divergent, and internally under each, there is a large tooth.

From A Monograph on the Sub-class Cirripedia With Figures of all the Species. by Charles Darwin

Shell oval, broad, thick; hinge margin subarcuated, the extremities winged and angulated; umbones prominent, the tips retuse.

From Zoological Illustrations, Volume III or Original Figures and Descriptions of New, Rare, or Interesting Animals by William Swainson

A true terminal umbo rests on the surface of the underlying scale, although several species with terminal umbos show the first stages of the dorsal umbo.

From The Genus Pinus by George Russell Shaw

Random Word

Spin the wheel and learn a new word!

---