n. 1. A number that can be represented in a number system with a given base, such as the decimal system, by a finite or infinite sequence of digits and a radix point. For example, 1.1 is a real number, as is 0.33333.... See also irrational number. Compare complex number, imaginary number. 2. A data type, in a programming language such as Pascal, that is used for storing, to some limit of precision, values that include both integer and fractional parts. See also double-precision, single-precision. Compare floating-point number, integer.