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

Linvill said he had personally tracked at least "a couple of hundred accounts the Russians hacked," but the real number was likely far higher.

From Barron's • May 29, 2026

The real number is higher, as some of the most troubled mortgages are taken out of the MBS pool of loans.

From The Wall Street Journal • May 3, 2026

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

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