"use of aromatic plant extracts and essential oils in massage or baths," by 1992, from French aromathérapie, which is attested from 1930s; see aroma + therapy.
Entries linking to aromatherapy
aroma n.
early 13c., "fragrant substance, spice" (a sense now obsolete), from Latin aroma "sweet odor," from Greek aroma "seasoning, a spice or sweet herb," which is of unknown origin. The meaning "fragrance, odor," especially an agreeable one, is from 1814. A hypercorrect plural is aromata. Related: Aromal.
therapy n.
1846, "medical treatment of disease," from Modern Latin therapia, from Greek therapeia "curing, healing, service done to the sick; a waiting on, service," from therapeuein "to cure, treat medically," literally "attend, do service, take care of" (see therapeutic).