real number

American  

[ree-uhl, reel] / ˈri əl, ril /

noun

Mathematics.

1. a rational number or the limit of a sequence of rational numbers, as opposed to a complex number.

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real number British  

noun

1. a number expressible as a limit of rational numbers See number

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real number Scientific  

/ rē′əl /

1. A number that can be written as a terminating or nonterminating decimal; a rational or irrational number. The numbers 2, −12.5, 3/7, and pi (π) are all real numbers.

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Etymology

Origin of real number

First recorded in 1905–10

Example Sentences

Most advocates believe the real number is at least 5,000.

From Slate • Mar. 25, 2026

Those bites cause about 30,000 deaths annually in sub-Saharan Africa, though some estimates suggest the real number is much higher.

From BBC • Feb. 1, 2026

"The real number of those killed is likely in the thousands," IHR's director Mahmood Amiry-Moghaddam said.

From Barron's • Jan. 14, 2026

Participants guessed that 47% of users share false or misleading news stories, even though existing research suggests the real number is about 8.5%.

From Science Daily • Dec. 17, 2025

Imagine that we’ve already got a perfect seating plan for the real numbers: every real number has a seat, and every seat is filled.

From "Zero: The Biography of a Dangerous Idea" by Charles Seife