deduction

[ dih-duhk-shuh n ]
/ dɪˈdʌk ʃən /

noun

the act or process of deducting; subtraction.
something that is or may be deducted: She took deductions for a home office and other business expenses from her taxes.
the act or process of deducing.
something that is deduced: His astute deduction was worthy of Sherlock Holmes.
Logic.
  1. 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.
  2. a conclusion reached by this process.Compare induction(def 4).

Origin of deduction

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

Related forms

non·de·duc·tion, nounpre·de·duc·tion, noun
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for deduction

British Dictionary definitions for deduction

deduction

/ (dɪˈdʌkʃən) /

noun

the act or process of deducting or subtracting
something, esp a sum of money, that is or may be deducted
  1. the process of reasoning typical of mathematics and logic, whose conclusions follow necessarily from their premises
  2. an argument of this type
  3. the conclusion of such an argument
logic
  1. a systematic method of deriving conclusions that cannot be false when the premises are true, esp one amenable to formalization and study by the science of logic
  2. an argument of this typeCompare induction (def. 4)

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Science definitions for deduction

deduction

[ dĭ-dŭkshən ]

The process of reasoning from the general to the specific, in which a conclusion follows necessarily from the premises.
A conclusion reached by this process.

Usage

The logical processes known as deduction and induction work in opposite ways. In deduction general principles are applied to specific instances. Thus, using a mathematical formula to figure the volume of air that can be contained in a gymnasium is applying deduction. Similarly, applying a law of physics to predict the outcome of an experiment is reasoning by deduction. By contrast, induction makes generalizations based on a number of specific instances. The observation of hundreds of examples in which a certain chemical kills plants might prompt the inductive conclusion that the chemical is toxic to all plants. Inductive generalizations are often revised as more examples are studied and more facts are known. If certain plants that have not been tested turn out to be unaffected by the chemical, the conclusion about the chemical's toxicity must be revised or restricted. In this way, an inductive generalization is much like a hypothesis.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

Culture definitions for deduction (1 of 2)

deduction

A process of reasoning that moves from the general to the specific. (Compare induction.)


Culture definitions for deduction (2 of 2)

deduction

A cost or expense subtracted from revenue, usually for tax purposes.


The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.