The Collaborative International Dictionary of English v.0.48:

Amaryllidaceae \Amaryllidaceae\ n.
   1. 1 a family of flowering plants including the snowdrop,
      narcissus, and daffodil; in some classification systems
      considered a subfamily of the Liliaceae.

   Syn: family Amaryllidaceae, amaryllis family
        [WordNet 1.5] Amaryllidaceous

WordNet (r) 3.0 (2006):

Amaryllidaceae
    n 1: snowdrop; narcissus; daffodil; in some classification
         systems considered a subfamily of the Liliaceae [syn:
         Amaryllidaceae, family Amaryllidaceae, amaryllis
         family]