'Idol' in the Bible

And they made a calf in those days, and offered sacrifice unto the idol, and rejoiced in the works of their own hands.

As concerning therefore the eating of those things that are offered in sacrifice unto idols, we know that an idol is nothing in the world, and that there is none other God but one.

Howbeit there is not in every man that knowledge: for some with conscience of the idol unto this hour eat it as a thing offered unto an idol; and their conscience being weak is defiled.

What say I then? that the idol is any thing, or that which is offered in sacrifice to idols is any thing?