Source : Webster's Revised Unabridged Dictionary (1913)

Archaeopteryx \Ar`ch[ae]*op"te*ryx\, n. [Gr. 'archai^os ancient
   + pte`ryx wing.] (Paleon.)
   A fossil bird, of the Jurassic period, remarkable for having
   a long tapering tail of many vertebr[ae] with feathers along
   each side, and jaws armed with teeth, with other reptilian
   characteristics.

Source : WordNet®

archaeopteryx
     n : extinct primitive toothed bird of the Jurassic period having
         a long feathered tail and hollow bones; usually
         considered the most primitive of all birds [syn: {archeopteryx},
          {Archaeopteryx lithographica}]