'Smoke' is PIE *smeugh- — Greek 'smykhein' (to smolder), Lithuanian 'smaugti' (to strangle). Dual nature.
A visible suspension of carbon or other particles in air, typically emitted from a burning substance.
From Old English smoca (smoke, fumes, vapour from a fire), related to the verb smeocan (to emit smoke, to smoke), from Proto-Germanic *smuko- (smoke) and the verbal root *smeukanan (to smoke, to smoulder), from PIE *smeugh- or *smug- (to smoke, to smoulder). The same PIE root appears in Greek smykhein (to smoulder slowly, to consume without open flame — the slow interior burning of a grievance), in Lithuanian smaugti (to choke, to strangle, evoking the suffocating quality of smoke), and possibly in Middle Irish much (smoke). The word has been remarkably stable across
'Smog' was coined in 1905 by London physician Harold Des Voeux as a portmanteau of 'smoke' and 'fog' to describe the toxic haze choking industrial British cities. Both halves of the word are Germanic, making it an entirely native English coinage — one of the few modern scientific terms that owes nothing to Latin or Greek.