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