Source : Webster's Revised Unabridged Dictionary (1913)

Crataegus \Cra*t[ae]"gus\ (kr?-t?"g?s), n. [NL., fr. Gr.
   krataigo`s.] (Bot.)
   A genus of small, hardy trees, including the hawthorn, much
   used for ornamental purposes.

Source : WordNet®

Crataegus
     n : thorny shrubs and small trees: hawthorn; thorn; thorn apple
         [syn: {genus Crataegus}]