de·​duc·​tion | \ di-ˈdək-shən How to pronounce deduction (audio) , dē- \

Definition of deduction

1a : an act of taking away deduction of legitimate business expenses
b : something that is or may be subtracted deductions from his taxable income
2a : the deriving of a conclusion by reasoning based on intuition rather than deduction specifically : inference in which the conclusion about particulars follows necessarily from general or universal premises (see premise entry 1 sense 1) — compare induction
b : a conclusion reached by logical deduction made the deduction that the suspect had been at the scene of the crime

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Synonyms & Antonyms for deduction



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Frequently Asked Questions About deduction

What is the difference between deduction and induction?

Deductive reasoning, or deduction, is making an inference based on widely accepted facts or premises. If a beverage is defined as "drinkable through a straw," one could use deduction to determine soup to be a beverage. Inductive reasoning, or induction, is making an inference based on an observation, often of a sample. You can induce that the soup is tasty if you observe all of your friends consuming it. Read more on the difference between deduction and induction

What is the difference between abduction and deduction?

Abductive reasoning, or abduction, is making a probable conclusion from what you know. If you see an abandoned bowl of hot soup on the table, you can use abduction to conclude the owner of the soup is likely returning soon. Deductive reasoning, or deduction, is making an inference based on widely accepted facts or premises. If a meal is described as "eaten with a fork" you may use deduction to determine that it is solid food, rather than, say, a bowl of soup.

What is the difference between deduction and adduction?

Adduction is "the action of drawing (something, such as a limb) toward or past the median axis of the body," and "the bringing together of similar parts." Deduction may be "an act of taking away," or "something that is subtracted." Both words may be traced in part to the Latin dūcere, meaning "to lead."

Examples of deduction in a Sentence

The government is offering new tax deductions for small businesses. What is your pay after the deductions have been taken out? His guess was based on intuition rather than deduction. Our deduction was based on the information given to us at the time. It was a logical deduction.
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Recent Examples on the Web After all, pointed out Ron Jahnke, a vice president in the private banking operation of Waukesha Bank in suburban Milwaukee, changes in income tax regulations have erased the value of a mortgage interest deduction for many homeowners. Joanne Cleaver,, 2 Sep. 2021 Add a few cats and dogs such as an increase in the size of the state-and-local tax deduction, and, voila, $5.5 trillion. The Editorial Board, WSJ, 20 July 2021 Through the power of deduction, Andrew S. is going on the one-on-one date. Ali Barthwell, Vulture, 7 July 2021 Wealthy folks around places like New York City and San Francisco, where local taxes are high, were hardest hit by the loss of the SALT deduction, and now their liberal congressmen are trying to fix it. Scott Jennings, CNN, 8 June 2021 In California, an analysis by the state’s tax board in 2018 estimated that loss of the full deduction may have cost state taxpayers $12 billion. Tal Kopan, San Francisco Chronicle, 10 May 2021 What the Democrats now seek is a restoration of the unlimited tax deduction that had previously been in place. The Editors, National Review, 6 Apr. 2021 Biden’s proposal or the revival of a state and local tax deduction that was not in it; none responded. Sarah Westwood, Washington Examiner, 2 Apr. 2021 Statements related by very strict rules of deduction. Alec Wilkinson, The New Yorker, 2 Mar. 2021

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'deduction.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of deduction

15th century, in the meaning defined at sense 1a

History and Etymology for deduction

see deduct

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Time Traveler for deduction

Time Traveler

The first known use of deduction was in the 15th century

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deduction new for old

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Last Updated

24 Sep 2021

Cite this Entry

“Deduction.” Dictionary, Merriam-Webster, Accessed 26 Sep. 2021.

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More Definitions for deduction



English Language Learners Definition of deduction

: the act of taking away something (such as an amount of money) from a total
: something (such as an amount of money) that is or can be subtracted from a total
: the act or process of using logic or reason to form a conclusion or opinion about something : the act or process of deducing something


de·​duc·​tion | \ di-ˈdək-shən How to pronounce deduction (audio) \

Kids Definition of deduction

2 : an amount deducted
3 : a conclusion reached by reasoning Her deduction was based on all the clues.



Legal Definition of deduction

1 : an amount allowed by tax laws to be subtracted from income in order to decrease the amount of income tax due — see also Internal Revenue Code — compare credit, exclusion, exemption
business deduction
: a deduction usually taken from gross income that is allowed for losses or expenses attributable to business activities or to activities engaged in for profit
charitable deduction
: a deduction allowed for a contribution to a charity usually that is qualified under the tax law (as sections 170 and 2055 of the Internal Revenue Code)
dependency deduction
: a deduction allowed to be taken in a set amount for a qualified dependent (as under sections 151 and 152 of the Internal Revenue Code)
itemized deduction
: a deduction for a specifically recorded item that is allowed to be taken from adjusted gross income if the total of such deductions exceeds the standard deduction
marital deduction
1 : a deduction allowed under the Internal Revenue Code to be taken from the gross estate that amounts to the value of any property interest which is included in the estate and which was given by a decedent to the surviving spouse provided that the interest is not terminable during the life of the survivor
2 : a deduction allowed under the Internal Revenue Code of the value of any gift inter vivos subject to gift tax by one spouse to the other
personal deduction
: a deduction allowed to be taken for losses or expenses that are not necessarily attributable to a business activity or an activity engaged in for profit
personal exemption deduction
: a deduction for an amount set by tax law that under section 151 of the Internal Revenue Code includes the dependency deduction
standard deduction
: a deduction of an amount set by tax law that is allowed to be taken from adjusted gross income unless the taxpayer elects to itemize deductions
2 in the civil law of Louisiana : an item of property or an amount that an heir has a right to take from the mass of the succession before any of it is partitioned (as for a debt owed by the deceased to the heir)

More from Merriam-Webster on deduction

Nglish: Translation of deduction for Spanish Speakers

Britannica English: Translation of deduction for Arabic Speakers Encyclopedia article about deduction


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