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

The host was primed, based on his own observations, to deduce that something highly suspicious was going on.

From Slate • Nov. 12, 2025

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

Related Words

• deduct
• glean
• infer
• presuppose
• surmise