Lewis & Short

baccar (bacchar), ăris, n. (baccăris, is, f., Plin. 12, 12, 26, § 45), = βάκχᾰρις, a plant having a fragrant root, from which an oil was expressed; also called nardum rusticum (cf. Plin. 12, 12, 26, § 45); acc. to Sprengel it is the Celtic valerian: Valeriana Celtica. Linn.; Plin. 21, 6, 16, § 29; Verg. E. 4, 19 (baccar herba est, quae facinum depellit, Serv.); 7, 27.