1. (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.

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