inhaler UK /ɪnˈheɪlə/US /ɪnˈheɪlɚ/ noun2 •A device with a canister holding medicine (either in powder or gas form) which is sprayed and inhaled by the patient, often for treating asthma and other respiratory diseases.Smokes incessantly Caporals, using a denicotinizing holder. At frequent intervals inhales from benzedrine inhaler. — 1953 •One who inhales.The exposure of the mouse lungs to smoke was, of course, relatively mild as compared with the exposure of the lungs of a human smoke-inhaler who gets true cancer. — 1963 formsinhalers