What does species mean?
Species has a precise biological meaning: a group of living organisms treated as a distinct form of life, usually capable of interbreeding with members of the same group and producing fertile offspring. It is the basic unit of biological classification and is used in discussions of evolution, conservation, biodiversity, and endangered organisms. The word can also be used more broadly for any particular kind or type, as in “a species of optimism,” although this use is usually more formal or literary than “type” or “kind.” A species is distinct from a genus, which is a broader group containing one or more species. The noun has the same singular and plural form, making it unusual among English nouns and giving rise to expressions such as “a species of animal” and “many species of plant.”
A group of living organisms considered a distinct biological form, generally able to interbreed with others of the same group and produce fertile offspring.
"The species has declined sharply over the past decade."
The singular and plural are both species.
A particular kind, type, or sort of person, thing, or activity.
"The novel portrays a species of political outsider."
This sense is more formal and literary than the common alternatives kind or type.
The singular and plural forms are identical. In formal or technical writing, context may occasionally make the number clear, but 'specieses' is not standard.
"Several species of fish inhabit these waters."
The word species looks like it should become 'specieses' in the plural, but its singular and plural forms are identical: one species, many species.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of species
Species comes from Latin species, meaning “appearance” or “kind,” a noun formed from specere, “to look at” or “to observe.” In Latin, the word developed into a sense of “form” or “kind,” from which its biological taxonomic meaning eventually emerged. English borrowed the word in the 16th century, and its scientific use was established through the history of biological classification. Related English words such as specific, specify, specimen, and spectacle also trace to the same Latin root.
Related word forms
How species is actually used
In biological contexts, species is a technical term with a defined meaning, though precise boundaries can be debated in some groups. In general contexts, the word often suggests a distinctive kind or type and may carry a slightly formal tone.
Easily confused with species
A genus is a broader taxonomic group containing one or more species, whereas a species is a more specific group within a genus.
A species is a formally recognized biological group, while a variety may refer more broadly to a type, form, or selection within a group.