Donkey

n. pl. Donkeys (dŏņ"kĭz).
  1. An ass; or (less frequently) a mule.
  2. A stupid or obstinate fellow; an ass.
    3. Donkey engine ,
    a small auxiliary engine not used for propelling, but for pumping water into the boilers, raising heavy weights, and like purposes.
    Donkey pump ,
    a steam pump for feeding boilers, extinguishing fire, etc.; -- usually an auxiliary.
    Donkey's eye (Bot.),
    the large round seed of the Mucuna pruriens, a tropical leguminous plant.