/ Dictionary / Index P photochemical smog: Meaning and Definition of Find definitions for: pho'tochem'ical smog' Pronunciation: [key] — Meteorol. Meteorol. air pollution containing ozone and other reactive chemical compounds formed by the action of sunlight on nitrogen oxides and hydrocarbons, esp. those in automobile exhaust. Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. photocell photochemistry Related Content Daily Word Quiz: inutiae Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language