ancillary

adjective

an·​cil·​lary ˈan(t)-sə-ˌler-ē 

-ˌle-rē,

 especially British  an-ˈsi-lə-rē

1

: subordinate, subsidiary

the main factory and its ancillary plants

2

: auxiliary, supplementary

the need for ancillary evidence

ancillary expenses

ancillary equipment

ancillary noun

Did you know?

If you’re already familiar with ancillary, pull up a chair and help yourself to a side dish of trivia. The word comes from the Latin word ancilla, meaning "a female servant," which also gave us the rarer English word ancilla, meaning "an aid to achieving or mastering something difficult." While the English ancilla (which made its debut a couple of centuries after ancillary) is unlikely to be encountered except in very specialized contexts (such as philosophy or quantum computing), ancillary picks up on the notion of providing aid or support in a way that supplements something else. In particular, the word often describes something that is in a position of secondary importance, such as the "ancillary products in a company's line."

Examples of ancillary in a Sentence

The lockout rocked the NHL, but among the ancillary benefits has been the emergence of young players who apprenticed for an additional season in the minors … —Michael Farber, Sports Illustrated, 21 Nov. 2005

I am in love with a man who is in love with boats. As far as ancillary loves are concerned, I understand things could be worse. Sadly, I do not love boats. —Ann Patchett, Gourmet, May 2003

Traditionally museums have been built to house collections, and for ancillary functions such as storage, conservation, administration, and education. —Jayne Merkel, Wilson Quarterly, Winter 2002

Paleolithic hunters and gatherers obtained an abundance of complete protein, mostly from wild game; their vegetable foods were an ancillary protein source. This pattern prevailed until agriculture transformed it, shifting the human diet away from meat and toward plant food. —S. Boyd Eaton et al., The Paleolithic Prescription, 1988

The company hopes to boost its sales by releasing ancillary products.

Recent Examples on the Web

Yet those plays became ancillary in the big picture. —Scott Dochterman, New York Times, 19 Oct. 2025

No one asked Bethea about this act, his views were ancillary and unnecessary to the moment that had been created. —Literary Hub, 16 Oct. 2025

What Freese calls ancillary services, or services where employee help is essential, could take more time. —Lia Russell, Sacbee.com, 14 Oct. 2025

Mahan said these measures would have the ancillary benefit of increasing the number of people who choose to take the services the city offers. —Devan Patel, Mercury News, 13 Oct. 2025

Word History

Etymology

see ancilla

First Known Use

1663, in the meaning defined at sense 1

Rhymes for ancillary

• accessary
• adversary
• arbitrary
• aviary
• axillary
• beriberi
• breviary
• budgetary
• capillary
• catenary
• cautionary
• cemetery

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Medical Definition

ancillary

1 of 2 adjective

an·​cil·​lary

ˈan(t)-sə-ˌler-ē, especially British an-ˈsil-ə-rē

: being auxiliary or supplementary

use of a drug as ancillary to surgical treatment

ancillary staff

ancillary diagnostic services

ancillary

2 of 2 noun

plural ancillaries

1

British : one who assists or is supplementary to another person

2

: a supplemental diagnostic or therapeutic medical service (as magnetic resonance imaging or radiotherapy)

Legal Definition

ancillary

adjective

an·​cil·​lary ˈan-sə-ˌler-ē, an-ˈsi-lə-rē 

1

: having a subordinate, subsidiary, or secondary nature

ancillary functions

an ancillary agreement

2

: serving as a supplement or addition

ancillary documents

3

: directly related

ancillary claims