a hairy weedy plant, Galeopsis tetrahit, of northern regions, having helmet-shaped pink, purple, and white flowers and toothed leaves: family Lamiaceae (labiates)
2.
any of various other plants of the genus Galeopsis
hemp nettle in American English
any of a genus (Galeopsis) of European plants of the mint family; esp., a common prickly weed (G. tetrahit) now found in the U.S.