owner: the person to whom a thing, animal, property, or even a debt belongs and who answers for it
At its root the word names the one who holds a thing as his own. An ox has a בַּעַל, and so does a pit dug in the ground, a borrowed animal, a field, a house, or money that is owed. Whoever owns the thing answers for it and has the say over it, which is why the same word can stretch from a plain possessor toward the one who is in charge.
This is the concrete legal core of the word, and most of it shows up in laws about property and liability, where the owner is the responsible party who bears the loss or makes good the damage. It reaches as far as the one who holds a claim: a creditor is the owner of the debt, the one to whom the money belongs.
The senses below shade that ownership from a simple possessor of an animal or object, to the head of a household, to the one who holds a right or a claim because the matter is his.