Source : Webster's Revised Unabridged Dictionary (1913)

Deduct \De*duct"\, v. t. [imp. & p. p. {Deducted}; p. pr. & vb.
   n. {Deducting}.] [L. deductus, p. p. of deducere to deduct.
   See {Deduce}.]
   1. To lead forth or out. [Obs.]

            A people deducted out of the city of Philippos.
                                                  --Udall.

   2. To take away, separate, or remove, in numbering,
      estimating, or calculating; to subtract; -- often with
      from or out of.

            Deduct what is but vanity, or dress.  --Pope.

            Two and a half per cent should be deducted out of
            the pay of the foreign troops.        --Bp. Burnet.

            We deduct from the computation of our years that
            part of our time which is spent in . . . infancy.
      --Norris.

   3. To reduce; to diminish. [Obs.] ``Do not deduct it to
      days.'' --Massinger.

Source : WordNet®

deduct
     v 1: make a subtraction [syn: {subtract}, {take off}] [ant: {add}]
     2: retain and refrain from disbursing; of payments; "My
        employer is withholding taxes" [syn: {withhold}, {recoup}]
     3: reason by deduction; establish by deduction [syn: {deduce},
        {infer}, {derive}]