Nonregular Number

A nonregular number, also called an infinite decimal (Havil 2003, p. 25), is a positive number that has an infinite decimal expansion. In contrast, a number that has a finite decimal representation such as  is said to be regular.

Nonregular numbers include repeating decimals, irrational numbers, and transcendental numbers.

REFERENCES:

Havil, J. Gamma: Exploring Euler's Constant. Princeton, NJ: Princeton University Press, 2003.