Source : Webster's Revised Unabridged Dictionary (1913)

Pyrus \Py"rus\, n. [L. pyrus, or better pirus, pear tree.]
   (Bot.)
   A genus of rosaceous trees and shrubs having pomes for fruit.
   It includes the apple, crab apple, pear, chokeberry, sorb,
   and mountain ash.

Source : WordNet®

Pyrus
     n : fruit trees native to the Old World: pears [syn: {genus
         Pyrus}]