| Noun | 1. | big sagebrush - aromatic shrub of arid regions of western North America having hoary leavessage brush, sagebrush - any of several North American composite subshrubs of the genera Artemis or Seriphidium genus Seriphidium, Seriphidium - woody plants grown chiefly for their silver or gray and often aromatic foliage; formerly included in the genus Artemisia | |