NOUN (2)

1. (linguistics) a large group of languages that are historically related;

2. (biology) the major taxonomic group of animals and plants; contains classes;

The Collaborative International Dictionary of English v.0.48:

Phylum \Phy"lum\, n.; pl. Phyla. [NL. See Phylon.]
   1. (Zool.) One of the larger divisions of the animal kingdom;
      a branch; a grand division.
      [1913 Webster]

   2. (Biol.) A series of animals or plants genetically
      connected.
      [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

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

Moby Thesaurus II by Grady Ward, 1.0:

108 Moby Thesaurus words for "phylum":
   affiliation, antonomasia, apparentation, binomial nomenclature,
   biological classification, biosystematics, biosystematy, biotype,
   birth, blood, bloodline, branch, brand, breed, cast, character,
   clan, class, classification, color, common ancestry, consanguinity,
   denomination, derivation, descent, description, designation,
   direct line, distaff side, extraction, family, feather,
   female line, filiation, form, genotype, genre, genus, glossology,
   grain, house, ilk, kidney, kin, kind, kingdom, label, line,
   line of descent, lineage, lot, make, male line, manner, mark, mold,
   nature, nomenclature, number, onomastics, onomatology, order,
   orismology, persuasion, place-names, place-naming, polyonymy, race,
   section, seed, sept, series, shape, side, sort, spear side,
   species, spindle side, stamp, stem, stirps, stock, strain, stripe,
   style, subclass, subfamily, subgenus, subkingdom, suborder,
   subspecies, subtribe, succession, superclass, superfamily,
   superorder, superspecies, sword side, systematics, taxonomy,
   terminology, the like of, the likes of, toponymy, tribe,
   trinomialism, type, variety