Source : Webster's Revised Unabridged Dictionary (1913)

Whortleberry \Whor"tle*ber`ry\, n. [AS. wyrtil a small shrub
   (dim. of wyrt wort) + E. berry. See {Wort}, and cf.
   {Huckleberry}, {Hurtleberry}.] (Bot.)
   (a) In England, the fruit of {Vaccinium Myrtillus}; also, the
       plant itself. See {Bilberry}, 1.
   (b) The fruit of several shrubby plants of the genus
       {Gaylussacia}; also, any one of these plants. See
       {Huckleberry}.

Source : WordNet®

whortleberry
     n 1: erect European blueberry having solitary flowers and
          blue-black berries [syn: {bilberry}, {whinberry}, {blaeberry},
           {Viccinium myrtillus}]
     2: blue-black berries similar to American blueberries [syn: {bilberry},
         {European blueberry}]