auxiliaries Play /ɔːɡˈzɪlɪəri/adjectiveProviding supplementary or additional help and support.auxiliary airport staffadditional,supplementary,supplemental,extra,reserve,backup,emergency,fallback,spare,substitute,othernounAn auxiliary person or thing.a nursing auxiliaryassistant,helper,aide SYNONYMS additionalbackupemergencyextrafallbackotherreservesparesubstitutesupplementalsupplementary