auxiliary

American  

[awg-zil-yuh-ree, -zil-uh-] / ɔgˈzɪl jə ri, -ˈzɪl ə- /

adjective

1. additional; supplementary; reserve.

   an auxiliary police force.

2. used as a substitute or reserve in case of need.

   The hospital has an auxiliary power system in case of a blackout.

   Synonyms:

   secondary, ancillary, backup

3. (of a boat) having an engine that can be used to supplement the sails.

   an auxiliary yawl.

4. giving support; serving as an aid; helpful.

   The mind and emotions are auxiliary to each other. Passion is auxiliary to art.

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noun

• auxiliaries
  plural

1. a person or thing that gives aid of any kind; helper.

   Synonyms:

   help, assistant, ally, aide

2. an organization allied with, but subsidiary to, a main body of restricted membership, especially one composed of members' relatives.

   The men's club and the ladies' auxiliary were merged into one organization.

3. auxiliary verb.

4. auxiliaries, foreign troops in the service of a nation at war.

5. Navy. a naval vessel designed for other than combat purposes, as a tug, supply ship, or transport.

6. Nautical. a sailing vessel carrying an auxiliary propulsion engine or engines.

auxiliary British  

/ ɔːɡˈzɪljərɪ, -ˈzɪlə- /

adjective

1. secondary or supplementary

2. supporting

3. nautical (of a sailing vessel) having an engine

   an auxiliary sloop

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noun

1. a person or thing that supports or supplements; subordinate or assistant

2. nautical

   1. a sailing vessel with an engine

   2. the engine of such a vessel

3. navy a vessel such as a tug, hospital ship, etc, not used for combat

Other Word Forms

Noun Inflected Forms

• auxiliaries
  plural

Etymology

Origin of auxiliary

1595–1605; < Latin auxiliārius assisting, aiding, helping, equivalent to auxili ( um ) aid, help ( aux ( us ) increased, augmented (past participle of augēre: aug- increase + -sus, variant of -tus past participle suffix) + -ilium noun suffix) + -ārius -ary

Explanation

When you're offering something in support of an already existing thing, you're offering something auxiliary. The auxiliary police will help out the regular police with things like directing traffic and crowd control when there's a special event in town. The Latin word auxilium means "help," and so auxiliary means something that "helps" by providing backup or support. Think of auxiliary verbs (sometimes called helper verbs), that provide support within a verb phrase, as "is" does in "Helen is playing." You can have an auxiliary engine in a car, an auxiliary cook at a restaurant, an auxiliary electrical network at a factory, or auxiliary troops standing by during battle. A "Ladies Auxiliary" functions as support for institutions such as churches, synagogues, or charities.

Example Sentences

See Examples For:

auxiliary auxiliaries

A cousin who happened to be an auxiliary police officer was let onto the scene.

From Slate ● Jul. 7, 2026

“When Mexico plays, many fans pray to the Virgin of Guadalupe to help them push the ball,” said Francisco Acero, auxiliary bishop of the Archdiocese of Mexico, who blessed the renovated stadium this year.

From The Wall Street Journal ● Jul. 3, 2026

Using auxiliary degrees of freedom is not a new concept in physics.

From Science Daily ● Jun. 16, 2026

They also managed to clamber aboard auxiliary craft, and the blue boat took all 20 fishermen on board, crew members said.

From Los Angeles Times ● Jun. 15, 2026

The ladies’ auxiliary of the Rotary Club canceled the azalea contest which was to be held in the gymnasium of the high school.

From "The Great Santini" by Pat Conroy

“We tend to undervalue and I would say underinvest in those unsexy but important capabilities like the oilers, like the auxiliaries, like the tenders. It’s the quiet backbone of American naval power.”

From The Wall Street Journal ● Apr. 10, 2026

Back then, California’s educational poobahs saw computers and typing as auxiliaries to learning instead of the essential skills we view them as today.

From Los Angeles Times ● Jan. 11, 2024

The group, made up of 3,530 people - 2,180 combatants and 1,350 auxiliaries - has maintained a bilateral ceasefire with the Colombian government since the beginning of the year.

From Reuters ● Apr. 16, 2023

Unison claims serious breaches of safety guidelines are occurring daily due to a lack of nurses, auxiliaries and porters.

From BBC ● May 13, 2022

I say, then, that the armies with which a prince defends his state are made up of his own troops, or mercenaries, or auxiliaries, or of mixed troops.

From "The Prince" by Niccolò Machiavelli

Related Words

• ancillary