Yes, ELECTOR is a Scrabble word!

Letter values in Scrabble US: E 1, L 1, E 1, C 3, T 1, O 1, R 1.

Is it a valid word?

ELECTOR is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

a citizen who has a legal right to vote
any of the German princes who were entitled to vote in the election of new emperor of the Holy Roman Empire