Where does “plain” come from?

Plain comes from Old French plain, from Latin planum, from Ancient Greek πλάνος, tracing back through Proto-Indo-European pleh₁- and pleh₂-.

plain (English): Flat, level; Simple; Obvious

Definitions

  1. Flat, level; Simple; Obvious

Ancestry of “plain”, step by step

plain traces back through 3 separate lines of ancestry.

via Middle English pleyn

StepLanguageWordMeaning
1Middle Englishpleynclear; unambiguous
2Anglo-NormanpleynAlternative form of plein
3Old Frenchplayn
4Old Frenchplainfull; plain; flat
5Latinplēnusfull; filled; complete
6Proto-Italicplēnosfull
7Proto-Indo-Europeanpl̥h₁nósfull
8Proto-Indo-Europeanpleh₁-to fill

via Anglo-Norman plainer

StepLanguageWordMeaning
1Anglo-Normanplainer
2Old FrenchpleindreAlternative form of plaindre; to complain, to...
3Latinplanctusstruck, beaten; bewailed, lamented, mourned;...
4Latin-tusForms the past participle of verbs; Forms...
5Proto-Italic-tus
6Proto-Indo-European-tusDerives action nouns from verb roots

via Middle French plain

StepLanguageWordMeaning
1Middle Frenchplainfull

Words derived from “plain

Every word from Proto-Indo-European pleh₁-
plain — Etymology, Origin & Word History | Etymology Explorer