# conjecture

/kənˈdʒɛkʃɝ/ (US) · /kəndʒˈɛktʃɐ/ (UK)

Source: https://englishreference.com/word/conjecture
Updated: 2026-08-08

## Senses

### 1. an unproven guess

noun · CEFR C1 · Formal

an opinion or idea you form without having all the facts.

For teachers: a conclusion or proposition based on incomplete evidence; a supposition that lacks definitive proof.

- The news report was based on conjecture rather than hard evidence.
- The historian admitted that his theory about the king's disappearance was mere conjecture, as no contemporary documents survived the fire.

Usage: Often used as an uncountable noun when referring to the act of guessing.

### 2. mathematical hypothesis

noun · CEFR C1 · Technical

a mathematical statement that appears to be true but has not been proven by logic yet.

For teachers: a mathematical proposition which has been conjectured to be true, but for which no proof has yet been found.

- The mathematician spent years trying to prove the famous conjecture.
- Goldbach's conjecture remains one of the oldest and best-known unsolved problems in number theory and all of mathematics.

Usage: In this domain, it is a countable noun referring to a specific named problem.

### 3. to guess

verb · CEFR C1 · Formal

to form an opinion or reach a conclusion using only a little information.

For teachers: to infer from inconclusive evidence; to propose a hypothesis without formal verification.

- Scientists conjecture that there may be water deep under the planet's surface.
- Archaeologists conjecture that the site served as a ceremonial center, though the lack of artifacts makes a definitive conclusion impossible.

Usage: Can be used transitively with a 'that' clause or as an intransitive verb.

## Examples

- His theory is based on conjecture rather than hard evidence.
- The news report was full of conjecture about the cause of the accident before the official investigation began.
- In the absence of historical records, any attempt to reconstruct the daily lives of these ancient people remains a matter of scholarly conjecture.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.