Webster's Revised Unabridged Dictionary · 1913

Home run

Home run , noun

Most home runs are made when the batter hits a fair ball out of the playing area on a fly, when the ball cannot be played by the defending team; if a batter circuits the bases while the ball is still inside the playing field, it is an inside-the-park home run.

(Baseball) a complete circuit of the bases made by the batter without being put out and without an error on the play; also, the hit on which the batter makes such a circuit; a four-base hit.