ox

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun An adult castrated bull of the genus Bos, especially B. taurus, used chiefly as a draft animal.
• noun A bovine mammal, especially one that has been domesticated.

from The Century Dictionary.

• noun Same as ox-coin.
• noun The adult male of the domestic Bos taurus, known in the natural state as a bull, whose female is a cow, and whose young is a calf; in a wider sense, an animal of the family Bovidæ and subfamily Bovinæ or Ovibovinæ; a bovine.
• noun In a restricted sense, the castrated male of Bos taurus, at least 4 years old and full-grown or nearly so. (See steer.) Such animals are most used as draft-animals and for beef.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Zoöl.) The male of bovine quadrupeds, especially the domestic animal when castrated and grown to its full size, or nearly so. The word is also applied, as a general name, to any species of bovine animals, male and female.
• noun (Zoöl.) the yak.
• noun (Zoöl.) the zebu.
• noun (Zoöl.) the banteng.
• noun (Zoöl.) See under Musk.
• noun See Ox gall, below.
• noun the fresh gall of the domestic ox; -- used in the arts and in medicine.
• noun [Obs.] ox marrow.
• noun (Zoöl.) a very large ray (Dicerobatis Giornæ) of Southern Europe. It has a hornlike organ projecting forward from each pectoral fin. It sometimes becomes twenty feet long and twenty-eight feet broad, and weighs over a ton. Called also sea devil.
• noun to be unfortunate; to know what sorrow is (because black oxen were sacrificed to Pluto).

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun Any bovine animal used as a beast of burden or for food, especially an adult castrated male of the domestic species.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun any of various wild bovines especially of the genera Bos or closely related Bibos
• noun an adult castrated bull of the genus Bos; especially Bos taurus