emperor

noun

1. The male monarch or ruler of an empire.
2. Any monarch ruling an empire, irrespective of gender, with "empress" contrasting to mean when consort to emperor
3. (political theory) Specifically, the ruler of the Holy Roman Empire; the world-monarch.“The Investiture Controversy was a conflict between the Emperor and the Pope.”
4. The fourth trump or major arcana card of the tarot deck.