Entry 1 sense Webster, 1913 Motherwort · Moth·er·wort · IPA /ˈmʌðəwəːt/ 01 n. A labiate herb (Leonurus Cardiaca), of a bitter taste, used popularly in medicine; lion's tail. 1. A labiate herb (Leonurus Cardiaca), of a bitter taste, used popularly in medicine; lion's tail.(Bot.)