This motto is important enough to American history that kids can rattle it off before they know what all the words mean. Just to be clear, here's what it does mean.

It's claiming that without representation in Parliament of colonials, the British government has no right to levy any taxes on them. They were supported by the Bill of Rights of 1689, which gave those rights to English citizens.

Makes sense, right? So send a representative to Parliament from the colonies and everything's fine.

Not so much. See, one representative wasn't really going to do a whole lot. Parliament would still be overwhelmingly British and, while one vote is better than zero votes, it's not enough to drive policy. The colonies were still going to be taxed according to what Parliament wanted, only this time it would be over a lone dissenting vote. Even if every colony got a representative you're dealing with the same routine landslides.

But this is a moot point, because the British didn't even bother with the whole representation thing. Maybe if they had, Americans would still be taking teatime and calling dessert "pudding."