mantissa Meaning, Definition & Usage

  1. noun the positive fractional part of the representation of a logarithm; in the expression log 643 = 2.808 the mantissa is .808
    fixed-point part.

WordNet

Man*tis*sa noun
Etymology
L., an addition, makeweight; of Tuscan origin.
Definitions
  1. (Math.) The decimal part of a logarithm, as distinguished from the integral part, or characteristic.

Webster 1913