What is the meaning of Floating-point_number?

A number written in the form a × b, e.g. 3.75 × 10 (a being the mantissa, b, the base and c, the exponent).

A real number held as a pair of integers, one representing the mantissa and the other representing the exponent. The base is normally 10, 16 or 256 depending on the computing system.

Source: wiktionary.org