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"