# auxiliary

/ɑɡˈzɪɫiɛɹi/ (US) · /ɔːksˈɪliəɹi/ (UK)

Source: https://englishreference.com/word/auxiliary
Updated: 2026-06-20

## Senses

### 1. providing extra help

adjective · CEFR C1 · Formal

giving extra help or support to a main person, group, or system.

For teachers: providing supplementary or additional help and support to a primary entity.

- The hospital hired auxiliary staff to help during the busy winter season.
- The main engine failed, but the auxiliary power unit kicked in immediately to keep the ship's navigation systems running.

### 2. held in reserve

adjective · CEFR C1 · Technical

kept ready to use if the main thing fails or if there is an emergency.

For teachers: functioning as a reserve or backup intended for use in exceptional circumstances.

- The building has an auxiliary water tank in case the city supply stops.
- Engineers designed an auxiliary cooling system to prevent a meltdown if the primary pumps were compromised.

### 3. a helper or backup

noun · CEFR C1 · Formal

a person or thing that provides extra help, especially in the military or a large organization.

For teachers: an individual or group that acts in a supportive or subsidiary capacity, often within a military or medical hierarchy.

- She volunteered as a nurse's auxiliary at the local clinic.
- The army relied heavily on local auxiliaries to navigate the difficult mountain terrain during the campaign.

### 4. grammar

noun · CEFR B2 · Technical

a helping verb like 'be', 'do', or 'have' that is used with another verb.

For teachers: a verb used in forming the tenses, moods, and voices of other verbs.

- In the sentence 'I am eating', the word 'am' is an auxiliary.
- The student struggled to distinguish between the primary auxiliary and the main lexical verb in complex passive constructions.

Usage: Common auxiliaries in English include 'be', 'do', and 'have', as well as modal verbs like 'can' and 'must'.

## Examples

- The hospital hired several auxiliaries to help the nursing staff.
- During the busy summer season, the local police department relies on a trained auxiliary to manage traffic near the beach.
- While the main fleet engaged the enemy directly, the auxiliary remained in the rear to manage logistics and provide medical support to the wounded sailors.

---

From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.