From BiblePortal Wikipedia

Webster's Dictionary [1]

(1): ( imp. & p. p.) of Mount

(2): ( a.) Placed on a suitable support, or fixed in a setting; as, a mounted gun; a mounted map; a mounted gem.

(3): ( a.) Seated or serving on horseback or similarly; as, mounted police; mounted infantry.

King James Dictionary [2]

Mount'Ed, pp. Raised seated on horseback placed on a carriage covered or embellished furnished with guns.