Added 9 October 2026 subphylum noun Categories: SocietyRare Words noun ! Definition from WordNet 3.1, Princeton University. More about subphylum at Wordnik → Where our words come from → (biology) a taxonomic group ranking between a phylum and a class. Related Words: superphylumphylumsuperfamilysubsectiondivisionsubgenussectionsubformparvorderinfrasectionsubregnumsubf. Back to today's word