Princeton's WordNet (3.00 / 1 vote) Rate this definition: opacity (noun) the phenomenon of not permitting the passage of electromagnetic radiation. opacity, opaqueness (noun) incomprehensibility resulting from obscurity of meaning. opacity, opaqueness (noun) the quality of being opaque to a degree; the degree to which something reduces the passage of light
Ozone is a gas that is naturally present in our atmosphere. It was first identified in laboratory experiments in 1839 and has the chemical formula O3 because an ozone molecule has three oxygen atoms attached to it.zone is a gas that is naturally present in our atmosphere. It was first identified in laboratory experiments in 1839 and has the chemical formula O3 because an ozone molecule has three oxygen atoms attached to it.
What is Ozone (O 3). Ozone (O3) is a gas that can form and react under the action of light and that is present in two layers of the atmosphere. High up in the atmosphere, ozone forms a layer that shields the Earth from ultraviolet rays. However, at ground level, ozone is considered a major air pollutant.