Noun | 1. | ![]() class - (biology) a taxonomic group containing one or more orders class Liliopsida, class Monocotyledonae, class Monocotyledones, Liliopsida, Monocotyledonae, Monocotyledones - comprising seed plants that produce an embryo with a single cotyledon and parallel-veined leaves: includes grasses and lilies and palms and orchids; divided into four subclasses or superorders: Alismatidae; Arecidae; Commelinidae; and Liliidae |