What was meant by the saying "no taxation without representation"?

The government should not be permitted to tax its citizens unless they are represented in it.

Explanation:

"No taxation without representation" was the motto of American colonists expressing objection to the British government. It suggested the inevitable American revolution.

American colonists had no say in the English government but were somehow still expected to pay taxes. They demanded their legal right to be represented in the government they gave their money to, otherwise they would refuse to be taxed.