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.

---

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

---

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

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

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

Don’t waste one brain cell trying to deduce the assassin.

From Los Angeles Times ● Jun. 5, 2026

But it’s still possible to compare newly emerged alphabets of the past with previously existing ones, and to deduce from letter forms which existing ones served as models.

From "Guns, Germs, and Steel: The Fates of Human Societies" by Jared M. Diamond

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

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

Marie-Laure deduces what she can from the sounds of their shoes: those are small, those weigh a ton, those hardly exist at all.

From "All the Light We Cannot See" by Anthony Doerr

Ms. Perry deduced immediately, without doubt, that he was dying.

From The Wall Street Journal ● Oct. 2, 2026

Plaintiffs’ net recoveries were still about 15% lower than they would have been without MICRA, Rand deduced.

From Los Angeles Times ● Jan. 16, 2026

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

From MarketWatch ● Dec. 4, 2025

From this, they deduced that DNA must have a three-dimensional, double-helix structure - like a twisted ladder with rungs formed of alternating salt and phosphate groups.

From BBC ● Nov. 7, 2025

“I have deduced that there is a relationship between these two masses that must be within certain parameters.”

From "October Sky" by Homer Hickam

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

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

From Slate ● May 29, 2024

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

Random Word

Spin the wheel and learn a new word!

---

Related Words

• conclude
• determine
• extrapolate
• infer
• surmise

---