adjuvant

Things that are adjuvant rarely get top billing—they're the supporting players, not the stars. But that doesn't mean they're not important. An adjuvant medicine, for example, can have a powerful healing effect when teamed up with another medicine or curative treatment. Adjuvant descends from the Latin verb adjuvare ("to aid"), which also gave English the nouns coadjutor ("assistant") and aid. These days, adjuvant tends to turn up most often in medical contexts, but it can also be used in the general sense of "serving to aid." Likewise, the noun adjuvant can mean "a drug or method that enhances the effectiveness of medical treatment" or simply "one that helps or facilitates."