[ozone] n [G Ozon, fr. Gk ozon, prp. of ozein to smell--more at odor] (ca. 1840) 1: a triatomic very reactive form of oxygen that is a bluish irritating gas of pungent odor, that is formed naturally in the atmosphere by a photochemical reaction and is a major air pollutant in the lower atmosphere but a beneficial component of the upper atmosphere, and that is used for oxidizing, bleaching, disinfecting, and deodorizing
2: pure and refreshing air -- ozo.nic adj