deduce

American  

[dih-doos, -dyoos] / dɪˈdus, -ˈdjus /

verb (used with object)

• deduces,
  present (3rd person singular)
• deduced,
  past participle,  past
• deducing
  present participle

1. to derive as a conclusion from something known or assumed; infer.

   From the evidence the detective deduced that the gardener had done it.

   Synonyms:

   determine, gather, reason, conclude

2. to trace the derivation of; trace the course of.

   to deduce one's lineage.

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deduce British  

/ dɪˈdjuːs /

verb

1. (may take a clause as object) to reach (a conclusion about something) by reasoning; conclude (that); infer

2. archaic to trace the origin, course, or derivation of

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Other Word Forms

Derived Forms

• deducibility
  noun
• deducibleness
  noun
• deducible
  adjective
• nondeducible
  adjective
• subdeducible
  adjective
• undeduced
  adjective
• undeducible
  adjective
• deducibly
  adverb

Inflected Forms

Participles

• deducing
  present
• deduced
  past

Conjugated Forms

Present

• deduce
  simple
• deduces
  simple
• have deduced
  perfect
• has deduced
  perfect
• am deducing
  progressive
• are deducing
  progressive
• is deducing
  progressive
• have been deducing
  perfect progressive
• has been deducing
  perfect progressive

Past

• deduced
  simple
• had deduced
  perfect
• was deducing
  progressive
• were deducing
  progressive
• had been deducing
  perfect progressive

Future

• will deduce
  simple
• will have deduced
  perfect
• will be deducing
  progressive
• will have been deducing
  perfect progressive

Etymology

Origin of deduce

First recorded in 1520–30; from Latin dēdūcere “to lead down, derive,” from dē- de- + dūcere “to lead”

Explanation

To deduce is to figure something out based on what you already know. When you see a person crying, it's easy to deduce that the person is sad. Unless they're happy, of course. Sometimes happy people cry. Derived from the Latin ducere, meaning "to lead," a person who deduces something is "leading" their mind from one idea to the next. Deduction is a noun from the verb deduce: it's what we call something that we learn when we deduce. Sherlock Holmes, the famous investigator created by Arthur Conan Doyle, was a master of deduction. He could deduce from a few small clues all of the facts of a murder case.

Example Sentences

See Examples For:

deduce deduces deduced deducing

Those who trust these writers’ capabilities with using comic book properties as springboards to examine thornier issues can probably deduce that “Lanterns” is employing it for a specific reason.

From Salon ● Aug. 14, 2026

The researchers concluded that vets could use such timed “up and go” tests to deduce whether a dog’s physical functions are declining between visits.

From The Wall Street Journal ● Jul. 30, 2026

As we deduce from the phone calls Maxine makes back home, she’s also going through an acrimonious divorce and has trouble connecting with her blasé teenage daughter.

From Los Angeles Times ● Jun. 26, 2026

This gives scientists a brief chance to measure how the more stable elements decay, then deduce the properties of the original particle.

From Barron's ● Mar. 17, 2026

Not that pinpointing another Book Scavenger user was an easy thing to deduce, even in the smallest and quietest of schools.

From "Book Scavenger" by Jennifer Chambliss Bertman

But Igor isn’t just adept at sniffing out truffles — he quickly deduces that she’s emotionally lost.

From Los Angeles Times ● Nov. 14, 2025

Then, with what it deduces about an individual's personality, the AI overlays that on top of what advertisers already know about people.

From BBC ● Nov. 13, 2025

But Bron is also, as Daniel Craig’s Benoit Blanc eventually deduces, an idiot.

From Seattle Times ● Mar. 7, 2023

He sees this dame as not hard to read and correctly deduces the contents, which impresses her.

From Salon ● Dec. 18, 2021

Because he saw that Major Rathbone’s wounds were caused by a knife, and because he hadn’t heard any gunshots during the performance, Leale deduces that Lincoln was stabbed.

From "Lincoln's Last Days: The Shocking Assassination that Changed America Forever" by Bill O'Reilly

The analysts split out the ETFs that they deduced retail investors put their money in.

From MarketWatch ● Dec. 4, 2025

On the subject of lyricism, as may be deduced by now, it was a largely disappointing year for new musicals—but not for musical-theater performances.

From The Wall Street Journal ● Nov. 26, 2025

He confidently illustrates what he’s deduced by drawing a grid on a whiteboard and yammering as his suspects and colleagues watch, slack-jawed.

From Salon ● Mar. 26, 2025

Several Syrian sources have deduced that out of almost 50 new military roles that have been announced, at least six have gone to foreigners.

From BBC ● Dec. 31, 2024

Elected officials deduced that a strong percentage of kids reading below their grade level by third grade would be needing a secure place to stay when they got older.

From "The Other Wes Moore: One Name, Two Fates" by Wes Moore

These include age verification tools such as facial age estimation, which must be "robust" in deducing whether a user is over 18.

From BBC ● Nov. 20, 2025

He soon reemerged, correctly deducing that there will always be starry-eyed sports fans willing to overlook pervasive failings.

From Slate ● May 29, 2024

Mattel originally conceived of the Dreamhouse for entirely capitalistic reasons, correctly deducing that kids lucky enough to get one would bother their parents to buy more Barbies for the original homeowner to play with.

From Salon ● Jul. 15, 2023

The IRS doesn’t track the race or ethnicity of taxpayers, but researchers used a methodology of deducing race by name and geography.

From Washington Times ● May 15, 2023

Am I right in deducing that these charges were incurred by you?

From "The Long-Lost Home" by Maryrose Wood

Related Words

• deduct
• glean
• infer
• presuppose
• surmise