phylum vs taxon

phylum

noun
  • A rank in the classification of organisms, below kingdom and above class; also called a divisio or a division, especially in describing plants; a taxon at that rank 

  • A large division of possibly related languages, or a major language family which is not subordinate to another. 

taxon

noun
  • A group of one or more populations of an organism or organisms seen by taxonomists to form a unit. 

How often have the words phylum and taxon occurred in a corpus of books? (source: Google Ngram Viewer )