Definition from Wiktionary, the free dictionary
- (mathematics) An element of the set of real numbers.; the set of real numbers include the rational numbers and the irrational numbers, but not all complex numbers.
- Every integer is a real number, but not vice versa.
- A real number can be regarded abstractly as an equivalence class of Cauchy sequences of real numbers.WP
- (computing) A floating-point number.
- Even if you pass sqrt an integer, it returns a real number.
Derived terms 
element of the real numbers
floating-point number — see floating-point number