If someone asks you what you have in common with the Antarctic icefish, you can say that you both belong to the same phylum, meaning the same taxonomic group: you are both vertebrates.

Biology types are probably already familiar with using the word phylum as a way to classify animals and plants. Mammals, including humans, are part of the phylum chordata, which also includes fishes, amphibians, reptiles, and birds. As you can see that’s a very broad category. Phylum comes above class and below kingdom in the biological classification system. The ranks get increasingly narrow, working all the way down to species, which is a closely related group.

Definitions of phylum
  1. noun
    (biology) the major taxonomic group of animals and plants; contains classes
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    Pyrrophyta, phylum Pyrrophyta
    a division of lower plants comprising unicellular and biflagellate algae that form starchy compounds
    Protozoa, phylum Protozoa
    in some classifications considered a superphylum or a subkingdom; comprises flagellates; ciliates; sporozoans; amoebas; foraminifers
    Cryptophyta, phylum Cryptophyta
    a phylum in the kingdom Protoctista
    Chordata, phylum Chordata
    comprises true vertebrates and animals having a notochord
    Cephalochordata, subphylum Cephalochordata
    Tunicata, Urochorda, Urochordata, subphylum Tunicata, subphylum Urochorda, subphylum Urochordata
    Craniata, Vertebrata, subphylum Craniata, subphylum Vertebrata
    fishes; amphibians; reptiles; birds; mammals
    Arthropoda, phylum Arthropoda
    jointed-foot invertebrates: arachnids; crustaceans; insects; millipedes; centipedes
    Pentastomida, subphylum Pentastomida
    tongue worms
    Porifera, phylum Porifera
    coextensive with the subkingdom Parazoa: sponges
    Cnidaria, Coelenterata, phylum Cnidaria, phylum Coelenterata
    hydras; polyps; jellyfishes; sea anemones; corals
    Ctenophora, phylum Ctenophora
    comb jellies; sea acorns; a small phylum formerly considered a class of Coelenterata
    Acanthocephala, phylum Acanthocephala
    phylum or class of elongated wormlike parasites that live in the intestines of vertebrates: spiny-headed worms
    Chaetognatha, phylum Chaetognatha
    arrowworms: a group of small active transparent marine worms
    Platyhelminthes, phylum Platyhelminthes
    Nemertea, Nemertina, phylum Nemertea, phylum Nemertina
    proboscis worms
    Pogonophora, phylum Pogonophora
    beard worms
    Rotifera, phylum Rotifera
    a phylum including: rotifers
    Aschelminthes, Nematoda, phylum Aschelminthes, phylum Nematoda
    unsegmented worms: roundworms; threadworms; eelworms
    Annelida, phylum Annelida
    segmented worms: earthworms; lugworms; leeches
    Mollusca, phylum Mollusca
    gastropods; bivalves; cephalopods; chitons
    Phoronida, Phoronidea, phylum Phoronida
    small phylum of wormlike marine animals
    Bryozoa, phylum Bryozoa, polyzoa
    marine or freshwater animals that form colonies of zooids
    Ectoprocta, phylum Ectoprocta
    coextensive with or a subphylum of Bryozoa
    Endoprocta, Entoprocta, phylum Entoprocta
    sometimes considered a subphylum of Bryozoa
    Cycliophora, phylum Cycliophora
    tiny marine organisms each the size of a period found in great numbers on lobsters' lips; identified tentatively in 1995 as a new phylum or as possible link between Entoprocta and Ectoprocta
    Brachiopoda, phylum Brachiopoda
    marine invertebrates that resemble mollusks
    Sipuncula, phylum Sipuncula
    peanut worms
    Echinodermata, phylum Echinodermata
    radially symmetrical marine invertebrates including e.g. starfish and sea urchins and sea cucumbers
    (botany) taxonomic unit of plants corresponding to a phylum
    Protista, division Protista
    eukaryotic one-celled living organisms distinct from multicellular plants and animals: protozoa, slime molds, and eukaryotic algae
    used only in former classifications: comprising what is now considered a heterogeneous assemblage of flowerless and seedless organisms: algae; bacteria; fungi; lichens
    Tracheophyta, division Tracheophyta
    in former classifications: comprising plants with a vascular system including ferns and fern allies as well as seed plants
    Bryophyta, division Bryophyta
    a division of nonflowering plants characterized by rhizoids rather than true roots and having little or no organized vascular tissue and showing alternation of generations between gamete-bearing forms and spore-bearing forms; comprises true mosses (Bryopsida) and liverworts (Hepaticopsida) and hornworts (Anthoceropsida)
    Pteridophyta, division Pteridophyta
    containing all the vascular plants that do not bear seeds: ferns, horsetails, club mosses, and whisk ferns; in some classifications considered a subdivision of Tracheophyta
    Spermatophyta, division Spermatophyta
    seed plants; comprises the Angiospermae (or Magnoliophyta) and Gymnospermae (or Gymnospermophyta); in some classification systems Spermatophyta is coordinate with Pteridophyta (spore producing plants having vascular tissue and roots) and Bryophyta (spore producing plants lacking vascular tissue and roots)
    in former classification systems: one of two major plant divisions, including all seed-bearing plants; superseded by the division Spermatophyta
    in former classification systems: one of two major plant divisions, including all plants that do not bear seeds: ferns, mosses, algae, fungi
    Pteropsida, subdivision Pteropsida
    used in former classifications to include all ferns and flowering plants and divided into the three classes Filicinae and Gymnospermae and Angiospermae
    Zygomycota, Zygomycotina, subdivision Zygomycota, subdivision Zygomycotina
    division of fungi having sexually produced zygospores
    Gymnomycota, Myxomycota, division Gymnomycota, division Myxomycota
    slime molds; organisms having a noncellular and multinucleate creeping vegetative phase and a propagative spore-producing stage: comprises Myxomycetes and Acrasiomycetes; in some classifications placed in the kingdom Protoctista
    Mastigomycota, Mastigomycotina, subdivision Mastigomycota, subdivision Mastigomycotina
    fungi in which the spores and gametes are motile; in some systems placed in the Phycomycetes group with the Zygomycota
    Lichenes, division Lichenes
    comprising the lichens which grow symbiotically with algae; sometimes treated as an independent group more or less coordinate with algae and fungi
    Eumycota, division Eumycota
    true fungi; eukaryotic heterotrophic walled organisms; distinguished from Myxomycota (funguslike slime molds): comprises subdivisions Mastigomycotina; Zygomycotina; Ascomycotina; Basidiomycotina; Deuteromycotina (imperfect fungi)
    Deuteromycota, Deuteromycotina, Fungi imperfecti, subdivision Deuteromycota, subdivision Deuteromycotina
    large and heterogeneous form division of fungi comprising forms for which no sexually reproductive stage is known
    Basidiomycota, Basidiomycotina, subdivision Basidiomycota, subdivision Basidiomycotina
    comprises fungi bearing the spores on a basidium; includes Gasteromycetes (puffballs) and Tiliomycetes comprising the orders Ustilaginales (smuts) and Uredinales (rusts) and Hymenomycetes (mushrooms, toadstools, agarics and bracket fungi); in some classification systems considered a division of kingdom Fungi
    Ascomycota, Ascomycotina, subdivision Ascomycota, subdivision Ascomycotina
    a large subdivision of Eumycota including Hemiascomycetes and Plectomycetes and Pyrenomycetes and Discomycetes; sac fungi; in some classification systems considered a division of the kingdom Fungi
    used in some classifications for the class Lycopsida: club mosses
    type of:
    taxon, taxonomic category, taxonomic group
    animal or plant group having natural relations
  2. noun
    (linguistics) a large group of languages that are historically related
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    type of:
    social group
    people sharing some social relation
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