Early 19th century; earliest use found in William Kirby (1759–1850), entomologist and naturalist. From post-classical Latin use of classical Latin plāga blow, stroke, wound, gash, either from ancient Greek πληγή (Doric πλᾱγά) blow, stroke (from a variant of the Indo-European base of πλήσσειν to strike), or a parallel formation from the base of classical Latin plangere, both Latin and Greek verbs deriving ultimately from the same Indo-European base as flaw.