Alternative spelling of first cause

(theology, philosophy, sometimes capitalized) An initial cause from which all other causes and effects follow.

(philosophy) The initial agent that is the cause of all things; the prime mover.

One's first instance of sexual intercourse. / Used other than figuratively or idiomatically: see first, time.

plural of first mate

(nautical) An officer on a merchant ship next in rank to the captain and responsible to the captain for the safety and security of the ship.

(US, humorous) A man who is the spouse of a sitting president.

(sports) The period of play before half time, as opposed to the second half.

(sports) Occurring in the first half

The most suitable and most optimal choice. / The prime cut. / The one with the highest ranking.