a single head of cattle: one ox, bull, or bullock
This is the word for one animal of the cattle kind, counted as an individual rather than as a herd. Where Hebrew wants to say a flock or stock of cattle together, it uses other words; this word picks out the single beast, the one ox standing in the field, dragging the plow, gored by another, or led to the altar.
Because it is just the one animal, the same word turns up across very different settings without changing its meaning. It is the working animal yoked to plow and threshing floor, the property a neighbor must return when it strays, the dangerous animal whose owner is liable when it gores a person, and the valuable beast offered in sacrifice. English translators reach for ox, bull, or bullock depending on the scene, but the Hebrew is making no such distinction: it is naming the kind of animal, not its exact age, sex, or role.
The laws of Exodus 21 and 22 use it more than any other book, because a single ox was a major piece of a household's wealth and a frequent cause of disputes between neighbors. In the sacrificial laws it names the cattle acceptable for offering, and in the prophets and wisdom books it stands for the patient, plodding strength of the domesticated animal.