The Collaborative International Dictionary of English v.0.48:
Ox \Ox\ ([o^]ks), n.; pl. Oxen. [AS. oxa; akin to D. os. G.
ochs, ochse, OHG. ohso, Icel. oxi, Sw. & Dan. oxe, Goth.
a['u]hsa, Skr. ukshan ox, bull; cf. Skr. uksh to sprinkle.
[root]214. Cf. Humid, Aurochs.] (Zool.)
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.
All sheep and oxen, yea, and the beasts of the field.
--Ps. viii. 7.
Note: The castrated male is called a steer until it attains
its full growth, and then, an ox; but if castrated
somewhat late in life, it is called a stag. The male,
not castrated, is called a bull. These distinctions are
well established in regard to domestic animals of this
genus. When wild animals of this kind are spoken of, ox
is often applied both to the male and the female. The
name ox is never applied to the individual cow, or
female, of the domestic kind. Oxen may comprehend both
the male and the female.
Grunting ox (Zool.), the yak.
Indian ox (Zool.), the zebu.
Javan ox (Zool.), the banteng.
Musk ox. (Zool.) See under Musk.
Ox bile. See Ox gall, below.
Ox gall, the fresh gall of the domestic ox; -- used in the
arts and in medicine.
Ox pith, ox marrow. [Obs.] --Marston.
Ox ray (Zool.), a very large ray (Dicerobatis Giornae) 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.
To have the black ox tread on one's foot, to be
unfortunate; to know what sorrow is (because black oxen
were sacrificed to Pluto). --Leigh Hunt.