genus
Americannoun
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Biology. the usual major subdivision of a family or subfamily in the classification of organisms, usually consisting of more than one species.
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Logic. a class or group of individuals, or of species of individuals.
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a kind; sort; class.
noun
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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 )
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logic a class of objects or individuals that can be divided into two or more groups or species
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a class, group, etc, with common characteristics
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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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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.”
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See Table at taxonomy
Other Word Forms
Derived Forms
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.
Vocabulary lists containing genus
"The Origin of Species by Natural Selection" by Charles Darwin: Essential Words
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We the People: Gen
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The ACT Science Test: Biology Review 1
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
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
The site has produced the oldest known member of the genus Homo and the earliest known Oldowan stone tools on Earth.
From Science Daily • May 16, 2026
Researchers from several South American institutions have identified a new species of crevice weaver spider, expanding what scientists know about the Pikelinia genus.
From Science Daily • May 1, 2026
Among them were small, rodent-like mammals belonging to the genus Cimolodon.
From Science Daily • Apr. 27, 2026
Humans first evolved in East Africa about 2.5 million years ago from an earlier genus of apes called Australopithecus, which means ‘Southern Ape’.
From "Sapiens: A Brief History of Humankind" by Yuval Noah Harari
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
