from The American HeritageĀ® Dictionary of the English Language, 4th Edition

  • adj. Having or resembling a knob or knoblike protuberance.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • adj. Having an umbo

from the GNU version of the Collaborative International Dictionary of English

  • adj. Having a conical or rounded projection or protuberance, like a boss.

from The Century Dictionary and Cyclopedia

  • Having a boss or umbo, as a shield or disk of any sort.
  • In zoology: Formed into an umbo, a boss, or a knob; button-like; umbonal; umbonic.
  • Having an umbo, as a shell; bearing umbones of this or that kind; umbonated: as, both valves strongly umbonate.
  • In botany, bearing an umbo or boss in the center, as the pileus of many species of Agaricus.


New Latin umbonatus. See umbo. (Wiktionary)


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