A taxonomic category of organisms ranking above an order and below a phylum or division. In modern taxonomic schemes, the names of classes end in -phyceae for the various groups of algae, -mycetes for fungi, and -opsida for plants (as in Liliopsida, the class of plants also termed monocotyledons). The names of classes belonging to phyla of the animal kingdom, however, are formed in various ways, as Osteichthyes the bony fishes, Aves, the birds, and Mammalia, the mammals, all of which are classes belonging to the subphylum Vertebrata (the vertebrates) in the phylum Chordata. See Table at taxonomy.

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