ahorse

adv

1. (archaic, not-comparable)On the back of a horse; on horseback.

   “He managed to escape ahorse.”

   “1817, Maria Edgworth, Ormond, Chapter 4, in Harrington, and Ormond, Tales, London: R. Hunter, Volume 2, p. 85, “By all that’s princely,” cried he, “then, that young Harry Ormond was intended for a prince, he sits a horse so like myself; and that horse requires a master hand to manage him.””

   “the right to proceed in peace, by whatever means he and his people saw fit, afoot or ahorse”

   “Two Romans ahorse were circling about four dismounted Cimbri, who stood back to back and glared.”