deduction

noun

de·​duc·​tion di-ˈdək-shən 

dē-

1

a

: an act of taking away

deduction of legitimate business expenses

b

: something that is or may be subtracted

deductions from his taxable income

2

a

: 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

Frequently Asked Questions

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."

Synonyms

• reduction
• discount

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.

Recent Examples on the Web

The increase in the state and local tax, or SALT, deduction provides the biggest boost to rich Americans, analysts said. —Medora Lee, USA Today, 24 Oct. 2025

Due to a coding error, a previous version of this interactive calculator incorrectly calculated certain taxes when an income, minus the standard deduction, equalled the ceiling of a particular tax bracket. —Rob Wile, NBC news, 22 Oct. 2025

The $85 million settlement fund will be distributed to qualified class members after deductions for fees, expenses and taxes. —Chase Jordan, Charlotte Observer, 21 Oct. 2025

To get a perspective, the IRS mileage deduction is 70 cents per mile. —Kathy Kristof, San Diego Union-Tribune, 20 Oct. 2025

Word History

Etymology

see deduct

First Known Use

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

Phrases Containing deduction

• payroll deduction

Rhymes for deduction

• abduction
• adduction
• conduction
• construction
• destruction
• eduction
• induction
• instruction
• obstruction
• production
• reduction
• seduction

Kids Definition

deduction

noun

de·​duc·​tion di-ˈdək-shən 

1

a

: an act of taking away

b

: something that is or may be subtracted

deductions from taxable income

2

a

: the drawing of a conclusion by reasoning

especially : reasoning in which the conclusion follows necessarily from a general rule or principle

b

: a conclusion reached by such reasoning

deductive

-ˈdək-tiv

adjective

deductively adverb

Legal Definition

deduction

noun

de·​duc·​tion

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

: 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

: 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)