Elector

One who elects, or has the right of choice; a person who is entitled to take part in an election, or to give his vote in favor of a candidate for office.

Hence, specifically, in any country, a person legally qualified to vote.

In the old German empire, one of the princes entitled to choose the emperor.

One of the persons chosen, by vote of the people in the United States, to elect the President and Vice President.

Pertaining to an election or to electors.

a citizen who has a legal right to vote