Adjunct and Extra

Adjunct noun - Something that is not necessary in itself but adds to the convenience or performance of the main piece of equipment.

Extra is a synonym for adjunct in supplement topic. In some cases you can use "Extra" instead the word "Adjunct" as a noun or an adjective, when it comes to topics like auxiliary.

Nearby Word: adjunction

Extra noun - An interchangeable part or piece of equipment that is kept on hand for replacement of an original.

Adjunct is a synonym for extra in addition topic. You can use "Adjunct" instead the word "Extra" as a noun or an adjective, if it concerns topics such as accessory, auxiliary.