Source : Webster's Revised Unabridged Dictionary (1913)

Sagebrush \Sage"brush`\, n.
   A low irregular shrub ({Artemisia tridentata}), of the order
   {Composit[ae]}, covering vast tracts of the dry alkaline
   regions of the American plains; -- called also {sagebush},
   and {wild sage}.

Source : WordNet®

Artemisia tridentata
     n : aromatic shrub of arid regions of western North America
         having hoary leaves [syn: {big sagebrush}, {blue sage}, {Seriphidium
         tridentatum}]