coefficient
Americannoun
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Mathematics. a number or quantity placed (generally) before and multiplying another quantity, as 3 in the expression 3x.
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Physics. a number that is constant for a given substance, body, or process under certain specified conditions, serving as a measure of one of its properties.
coefficient of friction.
adjective
noun
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maths
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a numerical or constant factor in an algebraic term
the coefficient of the term 3xyz is 3
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the product of all the factors of a term excluding one or more specified variables
the coefficient of x in 3axyz is 3ayz
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physics a value that relates one physical quantity to another
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A number or symbol multiplied with a variable or an unknown quantity in an algebraic term. For example, 4 is the coefficient in the term 4 x, and x is the coefficient in x (a + b).
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A numerical measure of a physical or chemical property that is constant for a system under specified conditions. The speed of light in a vacuum, for example, is a constant.
Other Word Forms
- coefficiently adverb
Etymology
Origin of coefficient
First recorded in 1655–65, coefficient is from the New Latin word coefficient- (stem of coefficiēns ). See co-, efficient
Explanation
In math and science, a coefficient is a constant term related to the properties of a product. In the equation that measures friction, for example, the number that always stays the same is the coefficient. In plain English, coefficient means "joining together to produce a result." Sometimes people use the word to talk about social phenomena, like the coefficient factors of vanity and self-loathing in a celebrity's alcoholic demise. But mostly you'll encounter it in math and science. In algebra, the coefficient is the number that you multiply a variable by, like the 4 in 4x=y. In chemistry, when you see a number in front of a chemical like 2H2o, you're looking at the coefficient.
Vocabulary lists containing coefficient
The ACT Math Test: Number and Quantity
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Expressions and Equations
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Algebra
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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.
They added that "the performances of French clubs competing on the European stage benefit French football as whole, with France currently occupying 6th place in the Uefa coefficient rankings for the 2025-26 season."
From BBC • Mar. 24, 2026
Based on all rolling 12-month periods since 2013, the correlation coefficient between these two assets is minus 27%.
From MarketWatch • Jan. 23, 2026
According to Kim, people often think first of Pearson's correlation coefficient when they hear the word agreement, since it is introduced early in statistics education and remains a fundamental tool.
From Science Daily • Nov. 14, 2025
However, standard measures of income inequality, such as the Gini coefficient, changed little over the period.
From The Wall Street Journal • Nov. 12, 2025
The first equation I needed to do was the one that defined the thrust coefficient.
From "October Sky" by Homer Hickam
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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.