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.
ozone layer definition. A band of ozone in the upper atmosphere. Ozone is a molecule made of three atoms of oxygen instead of the usual two. Note: The ozone layer absorbs harmful ultraviolet radiation from the sun and is thus very important to the health of human beings and other life forms on Earth.