The Collaborative International Dictionary of English v.0.48:

Multiply \Mul"ti*ply\, v. t. [imp. & p. p. Multiplied; p. pr.
   & vb. n. Multiplying.] [F. multiplier, L. multiplicare, fr.
   multiplex manifold. See Multitude, Complex.]
   1. To increase in number; to make more numerous; to add
      quantity to.
      [1913 Webster]

            Impunity will multiply motives to disobedience.
                                                  --Ames.
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   2. (Math.) To add (any given number or quantity) to itself a
      certain number of times; to find the product of by
      multiplication; thus 7 multiplied by 8 produces the number
      56; to multiply two numbers. See the Note under
      Multiplication.
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   3. To increase (the amount of gold or silver) by the arts of
      alchemy. [Obs.]
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   Multiplying gear (Mach.), gear for increasing speed.

   Multiplying lens. (Opt.) See under Lens.
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Moby Thesaurus II by Grady Ward, 1.0:

22 Moby Thesaurus words for "multiplying":
   crescendoing, crescent, expanding, growing, increase, increasing,
   incremental, intensifying, lengthening, multiple, multiplication,
   multiplication table, multiplier, on the increase, proliferating,
   proliferation, snowballing, spreading, swelling, tables,
   tightening, waxing