the.com/ozone hole

means A seasonal thinning of ozone in the upper atmosphere, especially over Antarctica, that lets through more of the sun's ultraviolet radiation than usual.

from 'Ozone' comes from Greek 'ozein,' meaning 'to smell' — coined in the 1840s by chemist Christian Friedrich Schönbein, who noticed the sharp odor given off by electrical sparks and the gas they produced. 'Hole' is just plain Old English for a gap or opening. The phrase 'ozone hole' itself is a 20th-century scientific coinage, popularized after researchers detected a dramatic seasonal thinning over Antarctica in the 1980s, later traced to chlorofluorocarbons — the chemicals once common in aerosol sprays and refrigerants.