• The buckthorn (Rhamnus Purshiana) of the Pacific coast of the United States, which yields cascara sagrada.
Cas'ca·ra buck'thorn` (Botany) The buckthorn ( Rhamnus Purshiana ) of the Pacific coast of the United States, which yields cascara sagrada. 
[n] - shrubby tree of United States Pacific coast
bearberry 3 bearwood noun shrubby tree of the Pacific coast of the United States; yields cascara sagrada