Auxiliary1. (a.) Conferring aid or help; helping; aiding; assisting; subsidiary; as auxiliary troops.
2. (n.) A helper; an assistant; a confederate in some action or enterprise.
3. (n.) Foreign troops in the service of a nation at war; (rarely in sing.), a member of the allied or subsidiary force.
4. (sing.) 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; etre and avoir, in French; avere and essere, in Italian; estar and haber, in Spanish.
5. (sing.) A quantity introduced for the purpose of simplifying or facilitating some operation, as in equations or trigonometric formulae.
Thesaurus Entries
abetting, accessory, accident, accidental, acolyte, addendum, addition, additional, adjunct, adjutant, adjuvant, adscititious, adventitious, agent, aid, aide, aide-de-camp, aider, aiding, alter ego, ancillary, another, appendage, appurtenance, appurtenant, ascititious, assistance, assistant, assisting, attendant, auxiliary verb, backing, best man, casual, circumstantial, coadjutant, coadjutor, coadjutress, coadjutrix, collateral, complementary, contingency, contingent, contributory, copula, defective verb, deponent verb, deputy, executive officer, extra, farther, finite verb, fortuitous, fostering, fresh, further, girl Friday, happenstance, help, helper, helpful, helping, helpmate, helpmeet, impersonal verb, incidental, inessential, infinitive, instrumental, intransitive, intransitive verb, lieutenant, linking verb, man Friday, mere chance, ministerial, ministering, ministrant, modal auxiliary, more, neuter verb, new, nonessential, not-self, nurtural, nutricial, other, paranymph, paraprofessional, peripheral, plus, reserve, second, secondary, servant, serving, sideman, spare, subordinate, subservient, subsidiary, superadded, superaddition, superfluous, supernumerary, supervenient, supplement, supplemental, supplementary, support, supporter, supporting, supporting actor, supporting instrumentalist, supportive, surplus, transitive, tributary, ulterior, unessential, upholding, verb, verb phrase, verbal