![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
mantissa (man-TIS-uh) - n., (math) the decimal part of a common logarithm; (computing) the significant decimal digits of a floating-point number; (obs.) an addition of little or no importance, as to a literary work.
That is, for the first two, the part that comes after the decimal point, so in log(643) = 2.808 the mantissa is .808, while 2 is the characteristic. This make a little sense if you remember that .808 is the part that tells you the digits of the original number and the 2 is the part that tells you that it is 6.43 hundreds, as opposed to 6.43 tens or 6.43 thousands or whatever magnitude. This use was introduced by mathematician Henry Briggs, and taken over in the modified meaning by computation. He derived it either from the obsolete sense or its root, Latin mantisa or mantissa, meaning a worthless addition, makeweight, said by a Roman grammarian (Sextus Pompeius Festus) to have been borrowed from Etruscan, and speculated by modern scholars to have been loaned to them by Gaulish speakers.
---L.
That is, for the first two, the part that comes after the decimal point, so in log(643) = 2.808 the mantissa is .808, while 2 is the characteristic. This make a little sense if you remember that .808 is the part that tells you the digits of the original number and the 2 is the part that tells you that it is 6.43 hundreds, as opposed to 6.43 tens or 6.43 thousands or whatever magnitude. This use was introduced by mathematician Henry Briggs, and taken over in the modified meaning by computation. He derived it either from the obsolete sense or its root, Latin mantisa or mantissa, meaning a worthless addition, makeweight, said by a Roman grammarian (Sextus Pompeius Festus) to have been borrowed from Etruscan, and speculated by modern scholars to have been loaned to them by Gaulish speakers.
---L.
