The Collaborative International Dictionary of English v.0.48:

Magnoliaceae \Magnoliaceae\ n.
   A natural family of plants, a subclass of the Magnoliidae; it
   includes the genera Liriodendron; Magnolia; Manglietia;
   and Michelia.

   Syn: family Magnoliaceae, magnolia family.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

Magnoliaceae
    n 1: subclass Magnoliidae: genera Liriodendron, Magnolia, and
         Manglietia [syn: Magnoliaceae, family Magnoliaceae,
         magnolia family]