·add. ·- The buckthorn (Rhamnus Purshiana) of the Pacific coast of the United States, which yields cascara sagrada.
·noun A genus (Rhamnus) of shrubs or trees. The shorter branches of some species terminate in long s...
Webster's Dictionary of the English Language
·- Holy bark; the bark of the California buckthorn (Rhamnus Purshianus), used as a mild cathartic or...