Phylum

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The hierarchy of biological classification's eight major taxonomic ranks. A kingdom contains one or more phyla. Intermediate minor rankings are not shown.

In biology, a phylum (plural: phyla)^{[note 1]} is a taxonomic rank below Kingdom and above Class. "Phylum" is equivalent to the botanical term division.^[1]

Although "phylum" is often used as if it were a clearly defined term, no satisfactory definition of it exists. In fact, "phylum" may be is a misnomer indicative of ignorance.^[2] Consequently the number of phyla varies from one author to the next. The relationships among phyla are becoming increasingly well known, and larger clades can be found to contain many of the phyla.