elector
person chosen to represent a group of individuals in casting a ballot in an election
Prince-Elector
member of the electoral college of the Holy Roman Empire, electing the King and then Emperor of the Romans
unpledged elector
nominated elector in a U.S. presidential election who has not pledged to support any particular candidate
faithless elector
member of the U.S. Electoral College who does not vote for the candidate for whom they had pledged to vote