Boyd’s Bible Dictionary:
(bellow). A term used generically for ox, cattle (Psa. 22:12). Bullock (Isa. 65:25); cow (Ezek. 4:15); oxen (Gen. 12:16). The “wild bull” (Isa. 51:20), and the “wild ox” (Deut. 14:5), mean probably the oryx.
Concise Bible Dictionary:
See Ox.
Strong’s Dictionary of Greek Words:
Meaning:
probably strengthened for όσχος (a shoot); a young bullock