"plant not valued for use or beauty," O.E. weod, uueod "grass, herb, weed," from P.Gmc. *weud- (cf. O.S. wiod, E.Fris. wiud), of unknown origin. Meaning "tobacco" is from 1606; that of "marijuana" is from 1920s. The verb meaning "to clear the ground of weeds" is late O.E. weodian.