I am trying to phrase something like:

We argue that introducing these concepts is likely to achieve ancillary goals.

Should I use auxiliary or ancillary here? Is there a difference in meaning?

  • Depends what you mean, right? In the interest of concise clear writing though, if you are not sure which of these words to use, it could be an indication that you could find a word that is more direct and meaningful. How about "supportive"? Or "secondary"?
    – tenfour
    Commented Mar 11, 2011 at 11:08

2 Answers 2


Ancillary carries with it the idea of support for main goals:

providing necessary support to the primary activities or operation of an organization, institution, industry, or system : the development of ancillary services to support its products.

Auxiliary has connotations of supplementary or "extra" help:

providing supplementary or additional help and support : an auxiliary nurse | auxiliary airport staff.


Use whichever works best for your meaning.

  • Interesting, I would have exactly switched those two connotations...
    – Uticensis
    Commented Mar 11, 2011 at 11:49
  • @Billare: I'd have given the same connotations as Robusto, but Merriam Webster basically gives both definitions for both words, even giving "auxiliary" as one of the definitions for "ancillary"...
    – psmears
    Commented Mar 11, 2011 at 12:50
  • 4
    @psmears, @Billare: All this means is that the line is getting blurred, and the two words are starting to be used interchangeably. It is worth noting that ancillary comes from the Latin ancilla (maidservant) while auxiliary comes from auxilium (help). The uses of auxiliary all seem to point to a "not part of the main thing, but extra" connotation. And, yes, we are making find distinctions here, but that is what the OP's question requires.
    – Robusto
    Commented Mar 11, 2011 at 13:08
  • I tend to agree with Robusto's distinction in connotations, but it is very interesting to see the confluence (?) in meaning and usage we apparently see.
    – mvexel
    Commented Mar 11, 2011 at 21:41
  • (Coming into the conversation much later) For whatever it's worth, both of these get used in technical and military applications quite often, where ancillary is always used in the context of supporting something else that's up and running, and auxiliary has a connotation of "the primary thing may or may not be working/available at the time".
    – user73481
    Commented Feb 24, 2020 at 17:37

The meaning of ancillary is also "additional, subsidiary".

Paragraph 19 was merely ancillary to paragraph 16.

If you wrote "ancillary goals" to mean "additional goals", then "ancillary goals" seems fine, to me.

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