mantissa (mantis a)

[L. manti a, man tis a, an addition, a makeweight; of Etruscan origin.] 1. A supplementary treatise; a les ser work following one on the same sub ject. - 2. The decimal part of a logarithm: so called as being additional to the characteristic or integral part. Thus, in the logarithm of 900 = 2.95424 the characteristic is 2, and the manti a is.95424. This use of the word was introduced by Henry Briggs, and is applied chiefly to Briggsian logarithms. See logarithm. 3. [cap.] In zoöl., a genus of mollusks.