genus

American  

[jee-nuhs] / ˈdʒi nəs /

noun

genera, plural genuses plural

1. Biology. the usual major subdivision of a family or subfamily in the classification of organisms, usually consisting of more than one species.

2. Logic. a class or group of individuals, or of species of individuals.

3. a kind; sort; class.

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genus British  

/ ˈdʒiːnəs /

noun

1. biology any of the taxonomic groups into which a family is divided and which contains one or more species. For example, Vulpes (foxes) is a genus of the dog family ( Canidae )

2. logic a class of objects or individuals that can be divided into two or more groups or species

3. a class, group, etc, with common characteristics

4. maths a number characterizing a closed surface in topology equal to the number of handles added to a sphere to form the surface. A sphere has genus 0, a torus, genus 1, etc

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genus Scientific  

/ jē′nəs /

genera plural

1. A group of organisms ranking above a species and below a family. The names of genera, like those of species, are written in italics. For example, Periplaneta is the genus of the American cockroach, and comes from the Greek for “wandering about.”

2. See Table at taxonomy

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genus Cultural  

1. In biology, the classification lower than a family and higher than a species. Wolves belong to the same genus as dogs. Foxes belong to a different genus from that of dogs and wolves, but to the same family. (See Linnean classification.)

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Other Word Forms

Derived Forms

• pseudogenus
  noun

Inflected Forms

Nouns

• genera
  plural
• genuses
  plural

Etymology

Origin of genus

1545–55; < Latin: race, stock, kind, gender; cognate with Greek génos. See gens, gender ¹, kin

Explanation

A genus is a class or group of something. In biology, it's a taxonomic group covering more than one species. This is a term used by biologists to classify more than one species under a larger umbrella. In biology, the word family describes the broadest group category, then genus, and then species. For example, primates are a family, and humans are a species within that family, but we're not in the same genus as macaques: macaques have their own genus. Dogs and wolves are so closely related they’re in the same genus. The plural of genus is genera.

Example Sentences

Jones said the best way to spot healthy peatland was the plants growing on it, "there'll be grasses, sedges, heathers, critically there will often be bog mosses of the genus sphagnum".

From BBC • Jul. 3, 2026

The spider, which belongs to the genus Propostira, was initially observed by biomedical researcher Greg Anderson - also a spider researcher and photographer.

From BBC • Jun. 23, 2026

The team analyzed mitochondrial genomes from preserved crocodiles belonging to the genus Crocodylus, including rare samples from the Seychelles population that vanished roughly 200 years ago.

From Science Daily • May 28, 2026

Because of its highly unusual anatomy, the insect was assigned to an entirely new genus named Carcinonepa.

From Science Daily • May 25, 2026

How was it possible that I’d never hear him ask me for a seven-letter word for something ever again, or what genus a particular species of bird falls under?

From "Red Flags and Butterflies" by Sheryl Azzam