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

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Etymology

Origin of deduce

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

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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

They deduce that, overnight, instruments have recorded a tightening cluster of earthquakes beneath Yellowstone’s vast caldera, which is roughly 55–70 kilometers across.

From Science Daily ● Sep. 22, 2026

I need to acknowledge up front that it is unwise for anybody—including me—to deduce any comprehensive conclusions about the Democratic Party and where it’s headed from Wisconsin’s gubernatorial primary last week.

From Slate ● Aug. 17, 2026

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

NFL games have replay after replay and you still need tenured MIT scientists to deduce what constitutes a catch.

From The Wall Street Journal ● Jul. 8, 2026

I was able to deduce from their body language that they had made up and this made me pleased because it showed how much better I was getting at reading body language.

From "The London Eye Mystery" by Siobhan Dowd

She correctly deduces that he knows nothing of personal tragedy, though she is clearly charmed by him.

From The Wall Street Journal ● Sep. 28, 2026

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

Then she deduces Heiss must have gotten the parka from Clark and asks where he is.

From Salon ● Feb. 5, 2024

He looks around and deduces that, in this very moment, he’s a character in a play that’s currently being written by Gunderson.

From Los Angeles Times ● Feb. 4, 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

“Agatha Christie’s Tommy & Tuppence,” on BritBox starting Wednesday, is “based on the stories and characters of Agatha Christie,” which the detectives among you have deduced has something to do with … Agatha Christie.

From Los Angeles Times ● Sep. 16, 2026

After scouring job postings online and talking with local ranchers, he’s deduced that the land might soon be transformed into one of the many large-scale data centers moving into Montana over the past year.

From The Wall Street Journal ● Jul. 11, 2026

Barclays deduced that the prediction markets with the most liquidity were able to provide valuable insights that can be compared to other available data.

From MarketWatch ● May 1, 2026

"We've kind of deduced it to be UVC radiation, the radiation that exists above the ozone layer because obviously there's no filter up there", he says.

From BBC ● Apr. 29, 2026

This, I have deduced, is a subset of human.

From "A Rover's Story" by Jasmine Warga

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

But Xu argues that the yuck factor is not a sound basis for deducing what's ethical and what's not.

From Salon ● May 13, 2025

Their system is becoming increasingly capable of deducing what is and is not alert-worthy on its own by using context clues, he said.

From Slate ● Dec. 11, 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

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Related Words

• conclude
• determine
• extrapolate
• infer
• surmise

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