Source : Webster's Revised Unabridged Dictionary (1913)

Phylon \Phy"lon\, n.; pl. {Phyla}. [NL., fr. Gr. ? race, tribe.]
   (Biol.)
   A tribe.

Phylum \Phy"lum\, n.; pl. {Phyla}. [NL. See {Phylon}.]
   (Zo["o]l.)
   One of the larger divisions of the animal kingdom; a branch;
   a grand division.

Source : WordNet®

phylum
     n 1: (linguistics) a large group of languages that are
          historically related
     2: (biology) the major taxonomic group of animals and plants;
        contains classes
     [also: {phyla} (pl)]

phyla
     See {phylum}