noun, plural: phyla or phylums
(2) A group of Classes with similar distinctive characteristics.
Examples: Class Mammalia (mammals), Class Aves (birds) and Class Ascidiacea (sea squirts) all belong to Chordate Phylum, which is a group of animals that have notochords at some time in their life cycle. Aside from Chordata, other well known phyla are the Mollusca, Porifera, Cnidaria, Platyhelminthes, Nematoda, Annelida, Arthropoda and Echinodermata, which all belong to Kingdom Animalia.
Word origin: New Latin ph[ymacr]lum, from Greek phūlon, class.