binomial

American  

[bahy-noh-mee-uhl] / baɪˈnoʊ mi əl /

noun

1. Algebra. an expression that is a sum or difference of two terms, as 3 x + 2 y and x 2 − 4 x.

2. Zoology, Botany. a taxonomic name consisting of a generic and a specific term, used to designate species.

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adjective

1. Algebra. consisting of or pertaining to two terms or a binomial.

2. Zoology, Botany. consisting of or characterized by binomials.

binomial British  

/ baɪˈnəʊmɪəl /

noun

1. a mathematical expression consisting of two terms, such as 3 x + 2 y

2. a two-part taxonomic name for an animal or plant See binomial nomenclature

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adjective

1. referring to two names or terms

binomial Scientific  

/ bī-nō′mē-əl /

1. A mathematical expression that is the sum of two monomials, such as 3 a + 2 b.

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Other Word Forms

• binomialism noun
• binomially adverb

Etymology

Origin of binomial

1550–60; < Late Latin binōmi ( us ) having two names (compare Latin binōminis ) + -al ¹. See bi- ¹, nominal

Explanation

Anything binomial consists of two terms (like x + 5) or has two names (like homo sapiens). Words starting with the prefix bi are related to the number two. The first meaning is one you might encounter in algebra class: a binomial has two terms. Often binomials are in parentheses, and they always have two parts: (X-Y) is a binomial because of the two variables: X and Y. The other type of binomial can be found in biology class: a two-part name that belongs to the system of distinguishing individual biological species, like canis familiaris: a dog.

Example Sentences

He is now widely regarded as the founder of modern taxonomy after introducing the binomial naming system and formally describing more than 10,000 species of plants and animals.

From Science Daily • Dec. 24, 2025

They seemingly prefer water so much, “hydro” is in their Latin binomial twice: Hydrochoerus hydrochaeris.

From Salon • Sep. 7, 2024

"There was a binomial system of nomenclature, a genus and species name that would be attached to things, but there were no rules other than that."

From Science Daily • Mar. 26, 2024

They played key roles in scientific achievements such as Carl Linnaeus's development of binomial nomenclature and Charles Darwin's theory of evolution.

From Scientific American • May 31, 2023

On the basis of the binomial probability distribution and the 1/12,000,000 figure, this probability can be determined to be about 8 percent—small, but certainly allowing for reasonable doubt.

From "Innumeracy: Mathematical Illiteracy and Its Consequences" by John Allen Paulos