Below the ranks of great lords, knights and bannerets on the field of battle were the men-at-arms, a term which encompassed a shifting group of men. Esquires below the rank of knight could be considered men-at-arms and when fighting in the 14c for Edward III would have been paid 12d a day. They would probably have been accompanied by a mounted archer. A man-at-arms might have been well born and aspire to a knighthood, or he could have been one of his shire's or borough's levy. This broad group, known in Latin as homines ad arma, was, however, distinct from the general rank and file, always on foot, known as homines armati.
Dictionary of Medieval Terms and Phrases. Christopher Coredon with Ann Williams.