\Mul"ti*pli`er\, n. [Cf. F. multiplier. Cf.
{Multiplicator}.]
1. One who, or that which, multiplies or increases number.
2. (Math.) The number by which another number is multiplied.
   See the Note under {Multiplication}.
3. (Physics) An instrument for multiplying or increasing by
   repetition or accumulation the intensity of a force or
   action, as heat or electricity. It is particularly used to
   render such a force or action appreciable or measurable
   when feeble. See {Thermomultiplier}.