auxiliary[ɔ:g'zɪlɪəri,ɒg-]
adjectiveproviding additional help or support.
noun(pluralauxiliaries) an auxiliary person or thing.
N. Amer.a group of volunteers who assist a church, hospital, etc. with charitable activities.
Origin
ME: from L.auxiliarius, fromauxilium'help'.
Thesaurusauxiliaryadjective
1an auxiliary power source: ADDITIONAL, supplementary, supplemental, extra, reserve, back-up, emergency, fallback, other.
2auxiliary nursing staff: ANCILLARY, assistant, support.
nouna nursing auxiliary: ASSISTANT, helper, ancillary.