deduction

UK: /dɪˈdʌkʃ^ən/ US: /dɪˈdʌkʃən/ ,(di duk′shən)

WordReference Random House Learner's Dictionary of American English © 2025

de•duc•tion /dɪˈdʌkʃən/   n. 

1. • [uncountable] the act or process of deducting.
   • [countable] something that is or may be deducted:
     a deduction of 10%.
2. • [uncountable] the act or process of inferring from known facts to a conclusion; the act or process of deducing:
     remarkable powers of deduction.
   • [countable] something deduced from known facts:
     It was the detective's deduction that the robbery was an inside job.
3. Philosophy
   • [uncountable] a process of reasoning in which a conclusion must follow from the premises presented;
     reasoning or concluding from the general to the particular or specific.
   • [countable] a conclusion reached by this process.

de•duc•tive /dɪˈdʌktɪv/  adj. See -duc-.

WordReference Random House Unabridged Dictionary of American English © 2025

de•duc•tion  (di duk′shən), n. 

1. the act or process of deducting;
   subtraction.
2. something that is or may be deducted:
   She took deductions for a home office and other business expenses from her taxes.
3. the act or process of deducing.
4. something that is deduced:
   His astute deduction was worthy of Sherlock Holmes.
5. Philosophy [Logic.]
   • a process of reasoning in which a conclusion follows necessarily from the premises presented, so that the conclusion cannot be false if the premises are true.
   • a conclusion reached by this process. Cf. induction (def. 4).

• Latin dēductiōn- (stem of dēductiō) a leading away. See deduct, -ion
• Anglo-French)
• late Middle English deduccioun (1400–50

Collins Concise English Dictionary © HarperCollins Publishers::

deduction / dɪˈdʌkʃən/ noun

1. the act or process of deducting or subtracting
2. something, esp a sum of money, that is or may be deducted
3. the process of reasoning typical of mathematics and logic, whose conclusions follow necessarily from their premises
4. the conclusion of such an argument
5. an argument of this type
   Compare induction4