tretinoin UK /tɹəˈtɪn.əʊ.ɪn/US /tɹəˈtɪn.oʊ.ɪn/ noun1 •The all-trans isomer of retinoic acid that is applied to the skin to treat severe acne and reduce facial wrinkles, roughness, and pigmented spots, and taken orally as a chemotherapy drug for acute promyelocytic leukemia. formstretinoins
