The Collaborative International Dictionary of English v.0.48:

Amaryllis \Am`a*ryl"lis\, n. [L. Amaryllis, Gr. ?, ?, the name
   of a country girl in Theocritus and Virgil.]
   1. A pastoral sweetheart.
      [1913 Webster]

            To sport with Amaryllis in the shade. --Milton.
      [1913 Webster]

   2. (bot.)
      (a) A family of plants much esteemed for their beauty,
          including the narcissus, jonquil, daffodil, agave, and
          others.
      (b) A genus of the same family, including the Belladonna
          lily.
          [1913 Webster]

WordNet (r) 3.0 (2006):

amaryllis
    n 1: bulbous plant having showy white to reddish flowers