Merriam-Webster Collegiate Dictionary - phylum

 noun  (plural phyla)  Etymology: New Latin, from Greek phylon tribe, race — more at phyl-  Date: 1876  1.  a. a direct line of descent within a group  b. a group that constitutes or has the unity of a ~; specifically a primary category in biological taxonomy especially of animals that ranks above the class and below the kingdom — compare division 10  2. a group of languages related more remotely than those of a family or stock