'Natural' in the Bible

Then I said, Ah, Lord! see, my soul has never been unclean, and I have never taken as my food anything which has come to a natural death or has been broken by beasts, from the time when I was young even till now; no disgusting flesh has ever come into my mouth.

The priests may not take for food any bird or beast which has come to a natural death or whose death has been caused by another animal.