Meaning of REAL NUMBER in English

In mathematics, a quantity that can be expressed as a finite or infinite decimal expansion.

The counting number s, integer s, rational number s, and irrational number s are all real numbers. Real numbers are used in measuring continuously varying quantities (e.g., size, time), in contrast to measurements that result from counting. The word real distinguishes them from the imaginary number s.

Britannica English dictionary.      Английский словарь Британика.