Deduction may refer to:

in logic:

  • Deductive reasoning, inference in which the conclusion is of no greater generality than the premises
  • Natural deduction, an approach to proof theory that attempts to provide a formal model of logical reasoning as it "naturally" occurs

in taxation:

  • Tax deduction, variable tax dollars that you can subtract, or deduct, from your gross income.
    • Itemized deduction, eligible expense that individual taxpayers in the United States can report on their Federal income tax returns
    • Standard deduction, dollar amount that non-itemizers may subtract from their income

Other uses:

  • Deduction (food stamps), used to calculate a household’s monthly food stamp benefit goods to help you eat