Betony \Bet"o*ny\, n.; pl. {Betonies}. [OE. betony, betany, F. betoine, fr. L. betonica, vettonica.] (Bot.) A plant of the genus {Betonica} (Linn.). Note: The purple or wood betony ({B. officinalis}, Linn.) is common in Europe, being formerly used in medicine, and (according to Loudon) in dyeing wool a yellow color.