Ancillary

adjective

Reinforcing, supplementing, or supporting the main elements or functions of something, especially from a secondary or less important position

noun

A secondary person or thing that bolsters the functioning or operation of the main component

Usage

While we may not always give much thought to the ancillary tools in our life, we would definitely notice them if they were to disappear. Typing a term paper without help from a spellchecker might take much longer than normal, since you'd have to be extra careful to catch any typos. Likewise, if you tried to take your coffee to go without a zarf, i.e. the cardboard sleeve, your hands might be practically burned by the time you finally set your drink down. If you find yourself taking something ancillary for granted, it might be because you're so reliant on its support that you've never imagined life without it.

Something ancillary extends, reinforces, or assists the main component of an object or system, but is not a primary piece itself. An ancillary instrument or element probably isn't very useful on its own, but it greatly bolsters or enables something that's actually important. For instance, a computer company might consider its technical support hotline an ancillary part of its business. A computer company doesn't really need a technical support division. However, a hotline would probably support the company's main mission — selling computers — by making customers feel more comfortable with its products. Similarly, white-out is an ancillary writing tool, because while it can’t record text on its own, it spares you from having to write everything perfectly the first time with your pen.

Additionally, ancillary can be used as a noun that identifies something that performs an assisting or supplemental function. Your bottle of white-out would serve as an ancillary to your pen, effacing errors you’d otherwise have to cross out more conspicuously. You may be able to live without an ancillary, but if it performs its duty well enough, you wouldn’t want to!

Example: Her notes served as an ancillary means of recalling the interview, in case her audio recorder ran out of battery power.

Example: Many cloud computing companies set up an additional server farm as an ancillary to their main facility.

Example: The organization's headquarters are in Downtown, but it also has an ancillary office in a local suburb.

Example: Almost every world leader is surrounded by ancillary support staff.

Origin

Emerging in English in the 1660s, ancillary comes from the Latin ancillaris, which means “of maids.” Ancillaris comes from ancilla, the diminutive of the Latin word for a female domestic servant, ancula. (Ancilla also briefly spent some time during the 20th century as an English noun meaning "something that helps with a difficult task or challenge".) Along with its masculine counterpart, anculus, ancula literally means “one who scurries around” and is a combination of the Latin ambi-, meaning “around” or “about,” and the Proto-Indo-European (PIE) root word kwel, meaning “to move about or in circles.” Ambi- comes directly from the Proto-Indo-European ambhi, which has the same meaning as its successor and is also related to other English words like ambivalent, ambiguous, and ambidextrous.

Similar Words

Auxiliary: If you're nervous about possibly confusing ancillary and auxiliary, don't worry: the two words have a lot of overlap. As an adjective, auxiliary means "additional" or "providing extra support or assistance". Ancillary can be used in this way too, but usually it also implies that whatever it's describing isn't as important as the main part that's being supported. With auxiliary, you might not be able to judge the supporter's importance without context. Ancillary is just a specific type of auxiliary, so if you're ever unsure, consider going with the latter. Or, you can try using this mnemonic: ancillary is like an ant because it ain’t as important. With all due respect to ants, obviously.

Also, perhaps because of its resemblance with the word auxiliary, ancillary is sometimes misspelled as ancilliary (with an incorrect extra "i" after the "ll"). There is always just one “i” in ancillary!

Example: In addition to its main power supply, the hospital has two auxiliary generators.

Accessory: Accessory is another word that's similar to ancillary, both in spelling and in meaning. As an adjective, accessory means "part of, adding to, or assisting something in a small or less important way." Something that's accessory may just be a minor component of something else; for instance, accessory actors in a play would probably just mill around in the background. In these cases, accessory often suggests that something is inessential. Like ancillary, though, accessory can also describe something as supporting a more important object or activity. Accessory things are more likely to have smaller impacts than ancillary things, which may be extremely helpful, even if they're inessential. Despite the minor difference, many people use these words interchangeably. If you want to be as accurate as possible, though, choose accessory if the thing you're describing is particularly insignificant, and stick with ancillary for things that make a clear difference.

Just like ancillary, accessory can also be used as a noun. Both words can refer to something that adds to or supports something more important than itself, especially in a nonessential way. Very often, an accessory is meant to make something more attractive. As a result, this form of accessory is a good choice when referencing an object's appearance; for instance, a chic bracelet might be a good accessory for highlighting a trendy new outfit. Both accessory and ancillary can name things that supplement something's function. You'd be fine calling a pair of Bluetooth headphones either an ancillary or an accessory to your smartphone. If you're having trouble deciding, keep in mind that ancillary is more commonly used as an adjective, while accessory is more common as a noun.

Example: Helium and krypton are accessory elements in Earth's atmosphere.

Example: A built-in navigation system is one of this car's best accessories.

In Literature

From Joseph Campbell’s The Hero With A Thousand Faces:

Once we have broken free of the prejudices of our own provincially limited ecclesiastical, tribal, or national rendition of the world archetypes, it becomes possible to understand that the supreme initiation is not that of the local motherly fathers, who then project aggression onto the neighbors for their own defense. The good news, which the World Redeemer brings and which so many have been glad to hear, zealous to preach, but reluctant, apparently, to demonstrate, is that God is love, the He can be, and is to be, loved, and that all without exception are his children. Such comparatively trivial matters as the remaining details of the credo, the techniques of worship, and devices of episcopal organization (which have so absorbed the interest of Occidental theologians that they are today seriously discussed as the principal questions of religion), are merely pedantic snares, unless kept ancillary to the major teaching.

In this passage, Campbell illustrates how the symbol of a world savior is actually shared by the myths and religions of cultures all over the world, and that they have in common certain key elements. He explains that things like teachings and methods of worship are just supplementary, or ancillary, embellishments individually tacked on by each belief system.

Mnemonic

An ancillary response to a question is secondary to the primary answer.
Ancillary helps the primary