auxiliary.

1. Providing support to a main activity, system, or group rather than forming its central part.

2. A verb used with a main verb to express features such as tense, aspect, voice or modality.

Use it for

Words that belong together

• auxiliary service
• auxiliary equipment

On the page

The auxiliary service handled overflow requests without replacing the central office.

An auxiliary generator kept the laboratory’s essential instruments running.

Usage notes

Primary category: academic / formal. Forms: Relational adjective; ordinary comparative and superlative generally not applicable. Legacy lexical fields mirror sense 1 only. Use numbered sense fields for all meanings. Established modern English lexical item. No separate regional spelling or grammatical inflection entry. Writing functions: analysis, comparison, evaluation. Disciplines: academic writing, institutional studies. Commonness: moderately common.