BioConcepts

taxonTaxon (ger.)

• A taxonomic group or unit, esp. when its rank in the taxonomic hierarchy is not specified. (OED 2013)
  category taxonomy

  1884

  [Sippe [als] jede systematische Einheit: Rasse, Varietät, Art, Gattung, Ordnung, Classe

  Nägeli, C. von (1884). Mechanisch-physiologische Theorie der Abstammungslehre: 10; cf. 231; 462.]

  1926

  Zwei oder mehr Individuen gehören dann zum selben Taxon, wenn sie im Rahmen des Isoreaktionsprinzips die gleichen Organisationsmerkmale besitzen

  Meyer, A. (1926). Logik der Morphologie im Rahmen einer Logik der gesamten Biologie: 137; cf. 127.

  1929

  I have sufficiently stressed the inefficacy of theoretical concepts when transferred from higher to lower levels where at best they merely introduce confusion. A very different picture is presented by the theoretical structures that have arisen naturally from the manipulation of the empirical data in any particular science and therefore belong, so to speak, to its own universe of discourse. I allude to such conceptions as the “species,” or “taxon” in taxonomy; the “lineage,” or “phylon” in phylogenetics

  Wheeler, W.M. (1929). Present tendencies in biological theory. The Scientific Monthly 28, 97-109: 107.
  

  1963

  Taxon. A group of organisms recognized as a formal unit at any level of a hierarchical classification; for instance, polar bears, carnivores, mammals, and chordates constitute taxa.

  Mayr, E. (1963). Animal Species and Evolution: 672.

  1982

  taxon (taxa) A taxonomic group of any rank, including all the subordinate groups; any group of organisms, populations, or taxa considered to be sufficiently distinct from other such groups to be treated as a separate unit; taxonomic unit.

  Lincoln, R.J., Boxshall, G.A. & Clark, P.F. (1982). A Dictionary of Ecology, Evolution and Systematics: 244.