de;duc;tion pronunciation: function: noun date: 15th century 1 a : an act of taking away lt;deduction of legitimate business expensesgt; b : something that is or may be subtracted lt;deductions from his taxable incomegt;2 a : the deriving of a conclusion by reasoning; specifically : inference in which the conclusion about particulars follows necessarily from general or universal premises — compare induction b : a conclusion reached by logical deduction
