floating-point number

Short definition from Wiktionary

Noun

1. 1
   A number written in the form a × bᶜ, e.g. 3.75 × 10³ (a being the mantissa, b, the base and c, the exponent).
2. 2
   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.