auxiliary
aux-il-ia-ry
noun
A person providing supplementary help or support, often in an organisation.
"The hospital employs many auxiliaries to assist nurses."
noun
A verb used to form tenses, moods, or voices.
"'Have' is an auxiliary verb in 'I have eaten'."
adjective
Providing supplementary or additional help, support, or resources.
"The auxiliary engine provided extra power when needed."
Thesaurus
Synonyms: appurtenant, adjunct, accessory, adjuvant, ancillary, supportive, aide, supplemental, secondary, subsidiary, supplementary