deduce

American  

[dih-doos, -dyoos] / dɪˈdus, -ˈdyus /

verb (used with object)

deduced, deducing

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

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

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

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

It is fair, then, to deduce we are likely to be at the beginning of the end of his trophy-laden tenure in the blue half of Manchester.

From BBC • Feb. 4, 2026

The detective and his team deduce that the plotters likely include government and industry officials in Canada and the U.S., as well as organized-crime figures and even members of the Quebec police force.

From The Wall Street Journal • Nov. 14, 2025

Rationalists—like lawyers relying on “common sense” reasoning—believe we can deduce truth from first principles.

From Slate • Sep. 26, 2025

From them, it should be possible to derive a complete system of knowledge embracing every aspect of the natural world, just as one can deduce the whole of Euclidean geometry from five axioms.

From "The Invention of Science" by David Wootton

Related Words

• deduct
• glean
• infer
• presuppose
• surmise