WordNet (r) 3.0 (2006):

Gymnospermae
    n 1: plants having naked seeds not enclosed in an ovary; in some
         systems considered a class (Gymnospermae) and in others a
         division (Gymnospermophyta); comprises three subdivisions
         (or classes): Cycadophytina (class Cycadopsida) and
         Gnetophytina (class Gnetopsida) and Coniferophytina (class
         Coniferopsida); in some classifications the Coniferophytina
         are divided into three groups: Pinophytina (class
         Pinopsida) and Ginkgophytina (class Ginkgopsida) and
         Taxophytina (class Taxopsida) [syn: Gymnospermae, class
         Gymnospermae, Gymnospermophyta, division
         Gymnospermophyta]