Pyrus

from WordNet (r) 3.0 (2006)

Pyrus
    n 1: fruit trees native to the Old World: pears [syn: {Pyrus},
         {genus Pyrus}]

from The Collaborative International Dictionary of English v.0.48

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.
   [1913 Webster]