forehorse

noun

1. The foremost horse in a team of horses; a lead horse

   “But the principal difficulties of travel within the capital were those created by the sheer volume of the traffic. The city's regulations prohibiting the entry of ironshod vehicles and requiring draymen to lead their forehorses were ignored.”

   “Scarcely had they passed the spot where I rested, when some one leaped from beneath the hedge, and seized the head of the forehorses. Another called upon the coachman to stop, and threatened him with instant death if he disobeyed.”

   “On the forehorses rode two chariot men; and on the four others, four henchmen in black gowns.”