S: (n) complement, accompaniment (something added to complete or embellish or make perfect) "a fine wine is a perfect complement to the dinner"; "wild rice was served as an accompaniment to the main dish"
S: (n) adjunct (a person who is an assistant or subordinate to another)
S: (n) adjunct (a construction that can be used to extend the meaning of a word or phrase but is not one of the main constituents of a sentence)
Adjective
S: (adj) accessory, adjunct, ancillary, adjuvant, appurtenant, auxiliary (furnishing added support) "an ancillary pump"; "an adjuvant discipline to forms of mysticism"; "The mind and emotions are auxiliary to each other"