any of a genus (Leonurus) of weedy plants of the mint family; esp., an Old World perennial (L. cardiaca) with pink or purplish flowers and a spiny, toothed calyx
See motherwort in American Heritage Dictionary 4
(mŭÞˈər-wûrtˌ, -wôrtˌ)
noun
Any of several Eurasian plants of the genus Leonurus, especially L. cardiaca, a weed having clusters of small purple or pink flowers and spine-tipped calyx lobes.