# Equivocation

*Also called: Ambiguity fallacy*

- **Cluster:** Broken structure — The form itself does not carry the conclusion
- **Page:** https://fallacy.wiki/fallacy/equivocation/
- **In Arabic:** https://fallacy.wiki/ar/fallacy/equivocation.md
- **Licence:** CC BY 4.0 — https://creativecommons.org/licenses/by/4.0/

## What it is

Using one word in two different senses within the same argument.

## In the wild

> Laws need lawmakers, so the laws of physics need one.

## How to answer it

Define the shared word once and hold that definition through the whole argument.

## Origin and naming

Glossed in logic as 'calling two different things by the same name.' It is the lexical half of the ambiguity family — the confusion sits inside a single word rather than in grammar. Sustained across a whole syllogism it becomes the medieval fallacy of the ambiguous middle.

## More places it shows up

- The contract says fees are 'reasonable', and both sides sign — years later a lawsuit reveals they agreed on the word, never the amount.
- A manager promises the role is 'flexible'; the hire hears remote-friendly, the manager meant available on weekends.
- A bank advertises 'free checking for everyone' — free to open, and free of any charge the bank chooses not to label a fee.
- A government report calls the program a 'success'; in its first use it means completed on time, in its second, that it worked.

## How to spot it

- Notice when the argument still sounds right until you substitute a dictionary definition for the key word at each use.
- Notice when agreement happens fast — everyone nodded at the same word for different reasons.
- Notice when the contested word carries one sense in the premise and a looser sense in the conclusion.

## Nearby

- [Amphiboly](https://fallacy.wiki/fallacy/amphiboly.md)
- [Fallacy of accent](https://fallacy.wiki/fallacy/accent.md)
- [Definist fallacy](https://fallacy.wiki/fallacy/definist.md)
- [Fallacy of four terms](https://fallacy.wiki/fallacy/four-terms.md)

## Read more

- [Wikipedia](https://en.wikipedia.org/wiki/Equivocation)
- [Fallacy Files](https://www.fallacyfiles.org/equivoqu.html)

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From fallacy.wiki — a bilingual field guide to 91 logical fallacies, published by phi holdings. Licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/): reuse freely with attribution to fallacy.wiki.