Source : Webster's Revised Unabridged Dictionary (1913)

Whahoo \Wha*hoo"\, n. (Bot.)
   An American tree, the winged elm. ({Ulmus alata}).

Source : WordNet®

Ulmus alata
     n : North American elm having twigs and young branches with
         prominent corky projections [syn: {winged elm}, {wing elm}]