decimal
Americanadjective
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pertaining to tenths or to the number 10.
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proceeding by tens.
a decimal system.
noun
noun
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Also called: decimal fraction. a fraction that has a denominator of a power of ten, the power depending on or deciding the decimal place. It is indicated by a decimal point to the left of the numerator, the denominator being omitted. Zeros are inserted between the point and the numerator, if necessary, to obtain the correct decimal place
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any number used in the decimal system
adjective
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relating to or using powers of ten
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of the base ten
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(prenominal) expressed as a decimal
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A representation of a real number using the base ten and decimal notation, such as 201.4, 3.89, or 0.0006.
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A decimal fraction.
Other Word Forms
Derived Forms
Inflected Forms
Nouns
Etymology
Origin of decimal
First recorded in 1600–10; from Medieval Latin decimālis “of tenths,” equivalent to Latin decim(a) “tenth” (derivative of decem “ten” ) + -ālis adjective suffix; see ten, -al 1
Explanation
A decimal is a fraction written in a special form. Instead of writing 1/2, for example, you can express the fraction as the decimal 0.5, where the zero is in the ones place and the five is in the tenths place. Decimal comes from the Latin word decimus, meaning tenth, from the root word decem, or 10. The decimal system, therefore, has 10 as its base and is sometimes called a base-10 system. Decimal can also specifically refer to a number in the decimal system. As an adjective, decimal means something related to this numbering system. The decimal point, for example, refers to the period that separates the ones place from the tenths place in decimal numbers.
Vocabulary lists containing decimal
Pi Day Vocabulary
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Perfect Ten: Dec, Cent, Mille
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Arithmetic
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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.
What mattered was mostly the initial integer, or what was “to the left of the decimal point,” rather than anything more exact.
From MarketWatch • Jun. 17, 2026
According to Fodor, the new work confirms the Standard Model to 11 decimal places and significantly narrows the chances that unknown physics is hiding in this particular measurement.
From Science Daily • May 19, 2026
That little decimal point wasn’t a lot, but then, artificial intelligence was barely a decimal point’s worth of those index funds a few years ago.
From Slate • Feb. 3, 2026
He was also chief secretary to the Treasury as the UK prepared to move to decimal currency.
From BBC • Oct. 25, 2025
“You know a lot about the Dewey decimal system for a motel employee.”
From "Mr. Lemoncello's Library Olympics" by Chris Grabenstein
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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.