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

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

His tales of Sherlock Holmes didn’t always present enough clues for readers—who could hardly be expected to compete with the brilliant detective—to deduce the solution on their own.

From The Wall Street Journal ● Feb. 20, 2026

“I shouldn’t have to go to much trouble to deduce it myself,” said the far-sighted civilian, “based on your friend’s description.”

From "Code Name Verity" by Elizabeth Wein

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

When one starts barking orders in Arabic, Sam quickly deduces that he is merely trying to communicate with passengers on a plane that just took off from Dubai.

From New York Times ● Jun. 27, 2023

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

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

The game, designed by Japanese artist Kotake Create, drops you into a white-tiled subway corridor that you’ll encounter again and again until the keys to unlock the title escape are deduced.

From Los Angeles Times ● Apr. 10, 2026

Using details like the number of shadows that fall on each guest’s neck, she deduced features such as the number of light sources the show uses, as well as the 360-degree studio setup.

From The Wall Street Journal ● Mar. 22, 2026

Even more remarkably, Leonardo deduced the way valves of a beating heart open and close—something he couldn’t have seen.

From "The Mona Lisa Vanishes" by Nicholas Day

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

Related Words

• deduct
• glean
• infer
• presuppose
• surmise