o·zone (??z?n?)n.1. An unstable, poisonous allotrope of oxygen, O3, that is formed naturally in the ozone layer from atmospheric oxygen by electric discharge or exposure to ultraviolet radiation, also produced in the lower atmosphere by the photochemical reaction of certain pollutants. It is a highly reactive oxidizing agent used to deodorize air, purify water, and treat industrial wastes.2. Informal Fresh, pure air.[German Ozon, from Greek ozon, neuter present participle of ozein, to smell.]o·zo?nic (?-z??n?k, ?-z?n??k), o?zon?ous (??z??n?s) adj.American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.ozone (???z??n; ???z??n) n1. (Elements & Compounds) a colourless gas with a chlorine-like odour, formed by an electric discharge in oxygen: a strong oxidizing agent, used in bleaching, sterilizing water, purifying air, etc. Formula: O3; density: 2.14 kg/m3; melting pt: ?192°C; boiling pt: ?110.51°C. Technical name: trioxygen 2. informal clean bracing air, as found at the seaside[C19: from German Ozon, from Greek: smell] ozonic, ?ozonous adjCollins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014o?zone (?o? zo?n, o??zo?n) n. 1. a form of oxygen, O3, produced when an electric spark or ultraviolet light passes through air or oxygen, that in the upper atmosphere absorbs ultraviolet rays, thereby preventing them from reaching the earth’s surface, but that near the earth’s surface is a harmful irritant and pollutant: used commercially for bleaching, oxidizing, etc. 2. ozone layer. 3. fresh air. [