prop. n. A class of plants comprising seed plants that produce an embryo with a single cotyledon and parallel-veined leaves: grasses; lilies; palms; and orchids. It is divided into four subclasses or superorders: Alismatidae; Arecidae; Commelinidae; and Liliidae.
Syn. -- class Monocotyledones, Monocotyledonae, class Monocotyledonae, Liliopsida, class Liliopsida. [ WordNet 1.5 ]