mantissaPronunciation: /manˈtɪsə/Definition of mantissa noun 1 Mathematics the part of a logarithm after the decimal point. 2 Computing the part of a floating-point number which represents the significant digits of that number. Origin: mid 17th century: from Latin, literally 'makeweight', perhaps from Etruscanmantissa in other Oxford dictionaries Definition of mantissa in the US English dictionary
