The Collaborative International Dictionary of English v.0.48:

hippeastrum \hippeastrum\ n.
   An amaryllis of tropical America (Hippeastrum puniceum)
   often cultivated as a houseplant for its showy white to red
   flowers.

   Syn: Hippeastrum puniceum.
        [WordNet 1.5] Hipped

WordNet (r) 3.0 (2006):

hippeastrum
    n 1: amaryllis of tropical America often cultivated as a
         houseplant for its showy white to red flowers [syn:
         hippeastrum, Hippeastrum puniceum]