What does Exodus 21:24 mean?

If someone loses an eye, you owe an eye. If they lose a tooth, you owe a tooth. The same goes for a hand, a foot, a burn, a wound, or a bruise. Exodus 21:24 - Modern Text Bible

(This is the 'eye for an eye' rule. The idea is that the punishment should fit the harm done, not go beyond it.)