deduce

deduce — verb

1. to use the facts or evidence you have to figure out what must be true or what pr

1.verbtransitiveB2
Definition

to use the facts or evidence you have to figure out what must be true or what probably happened

Example

From the footprints on the floor, Tunde deduced that Nellie had entered through the back door.

deduce from [evidence] + that-clause

A geologist studied the rock samples and deduced the age of the ancient volcano.

deduce + noun phrase object

Common collocations
  • deduce from [evidence]
  • deduce that [clause]
  • deduce what/where/when/why/how
  • deduce the cause/identity/meaning/source/truth
Synonyms
  • infer

    broader meaning — includes understanding from context or implication, not necessarily by deliberate step-by-step reasoning

  • conclude

    focuses on the endpoint or decision reached, which may come from intuition or discussion rather than logical evidence

  • reason

    highlights the mental process of thinking logically rather than the conclusion itself

  • work out

    informal equivalent; common in everyday speech

Grammar Patterns

deduce + that-clause

deduce + wh-clause (what/where/when/why/how)

deduce + noun phrase + from + noun phrase

Usage Note

Commonly followed by a that-clause, a wh-clause (what, where, why, how), or a noun phrase. The source of evidence is introduced by from: deduce from [evidence] that…

Common Mistakes

From the evidence, I deduce he is lying.
From the evidence, I deduce that he is lying.
The conjunction 'that' is standard after 'deduce' in formal writing, though it can be omitted in casual speech.
I deduced that she was tired from her yawning.
I deduced from her yawning that she was tired.
The 'from' phrase more naturally comes right after the verb, or at the beginning of the sentence.

Word family

  • deduction
    nounB2
  • deductive
    adjectiveC1
  • deducible
    adjectiveC1

Synonym discussion

Sense: verb/1

Deduce suggests a step-by-step conclusion drawn from specific evidence — you examine facts and reach a definite finding. Infer is broader: it can mean 'understand from context' without deliberate reasoning, such as inferring someone's mood from their tone of voice. Conclude puts the focus on the endpoint of a process — you may conclude after deduction, intuition, or group discussion. Reason highlights the mental process of thinking logically rather than the result. Work out is the informal equivalent, common in everyday spoken English. For example, a detective deduces the suspect's identity from a thread left at the crime scene, while a friend infers your sadness from your silence.

infer ↗conclude ↗reason ↗work out ↗

Common collocations

Nouns

Adverbs

Phrases

  • it can be deduced that...
  • from this we can deduce...

Prepositions

Etymology

LatinEnglish

Comes from Latin deducere, meaning 'to lead down', formed from de- ('down from') and ducere ('to lead'). In Latin it meant 'to lead or bring someone somewhere'; by the 1500s English speakers used it for 'drawing a conclusion from evidence', as if leading the mind down a logical path to an answer.