Auxilia, a pecuniary tribute under the feudal system, paid by a vassal to his lord on particular occasions; originally a mere gift, which, in process of time, became a demandable right. The aids of this kind were chiefly three, viz.:—1st, When the lord made his eldest son a knight; 2d, To provide a dower when he gave his eldest daughter in marriage; 3d, To ransom his lord when taken prisoner. The amount of the first two was limited by statute, but the last was, of course, uncertain.