auxiliary
//ɔːɡˈzɪl.jə.ri//
Adjective
Providing supplementary or additional help and support.
The hospital has an auxiliary power generator in case of emergencies.
(Of equipment or a device) held in reserve for use when needed as a backup.
The hospital has an auxiliary power generator in case of emergencies.
(In grammar) relating to or denoting a verb used to form tenses, moods, and voices of other verbs, such as 'be', 'have', and 'do'.
In English, 'have' is an auxiliary verb used to form perfect tenses.
Noun
A person or thing providing supplementary or additional help and support.
The hospital hired several auxiliaries to assist the nursing staff.
A group of troops or ships providing additional support to a main force.
The general called for auxiliaries to reinforce the front line.
(In grammar) an auxiliary verb.
In English, 'have' and 'be' are common auxiliaries used to form different tenses.