Auxiliary, n.; pl. Auxiliaries (.
1. A helper; an assistant; a confederate in some action or enterprise.
2. (Mil.) pl.
Foreign troops in the service of a nation at war; (rarely in sing.), a member of the allied or subsidiary force.
3. (Gram.)
3 more senses
A verb which helps to form the voices, modes, and tenses of other verbs; -- called, also, an auxiliary verb; as, have, be, may, can, do, must, shall, and will, in English; être and avoir, in French; avere and essere, in Italian; estar and haber, in Spanish.
4. (Math.)
A quantity introduced for the purpose of simplifying or facilitating some operation, as in equations or trigonometrical formulæ. Math. Dict.
1 other Webster entry under this spelling
Auxiliary, a.
Conferring aid or help; helping; aiding; assisting; subsidiary; as auxiliary troops. Auxiliary scales (Mus.), the scales of relative or attendant keys. See under Attendant, a. -- Auxiliary verbs (Gram.). See Auxiliary, n., 3.
Shades of meaning
An auxiliary is a person or thing that helps in a subordinate capacity. Allies unite as equals; auxiliaries are, at least technically, inferiors or subordinates. Yet the auxiliary is more than a mere assistant. The word is oftenest found in the plural, and in the military sense; auxiliaries are troops of one nation uniting with the armies, and acting under the orders, of another. Mercenaries serve only for pay; auxiliaries often for reasons of state, policy, or patriotism as well. Compare accessory; appendage.
Prepositions
The auxiliaries of the Romans; an auxiliary in a good cause; an auxiliary to learning.