Source : Webster's Revised Unabridged Dictionary (1913)

Coltsfoot \Colts"foot`\, n. (Bot.)
   A perennial herb ({Tussilago Farfara}), whose leaves and
   rootstock are sometimes employed in medicine.

   {Butterbur coltsfoot} (Bot.), a European plant ({Petasites
      vulgaris}).

Source : WordNet®

Tussilago farfara
     n : perennial herb with large rounded leaves resembling a colt's
         foot and yellow flowers appearing before the leaves do;
         native to Europe but now nearly cosmopolitan; used
         medicinally especially formerly [syn: {coltsfoot}]