# Definition of mantissa in English:

## mantissa

### noun

• 1Mathematics
The part of a logarithm after the decimal point.

• ‘By choosing appropriate mantissas and exponents, we can increase the resolution at shallower depths and degrade it at greater depths.’
• ‘The mantissa provides the significant information, or digits, and the exponent provides a scaling factor that shows how big the number is.’
• ‘Sharp and completely accurate visions of hexadecimal mantissas and binary fractions floated about my head, along with the sure and certain knowledge of how to convert them to something more useful.’
• 2Computing
The part of a floating-point number which represents the significant digits of that number.

• ‘If you recall, run-of-the-mill DSPs typically store numbers as a floating-point, 24-bit mantissa and an 8-bit exponent.’
• ‘In these cases, the 24-bit fixed standard is equivalent to the 24-bit mantissa, plus 8-bit exponent used in the 32-bit, floating-point version.’
• ‘Double-precision fixed-point would employ two times 24, or a 48-bit word length; double-precision floating-point would use a two times 32, or 64-bit mantissa.’

### Origin

Mid 17th century: from Latin, literally ‘makeweight’, perhaps from Etruscan.

/manˈtɪsə/