The Collaborative International Dictionary of English v.0.48:

Cycadaceae \Cycadaceae\ n.
   a natural family of ancient palmlike plants closely related
   to ferns in that fertilization is by means of spermatozoids.

   Syn: family Cycadaceae, cycad family.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

Cycadaceae
    n 1: ancient palmlike plants closely related to ferns in that
         fertilization is by means of spermatozoids [syn:
         Cycadaceae, family Cycadaceae, cycad family]