# treatise

/ˈtɹitəs/ (US) · /tɹˈiːtɪz/ (UK) · CEFR C1 · Noun

Source: https://englishreference.com/word/treatise
Updated: 2026-05-06

## Definition

a long and serious piece of writing that explains a subject in great detail. It is usually more formal and deeper than a simple essay.

For teachers: a formal and systematic written discourse on a specific subject, generally longer and more exhaustive than an essay. It aims to present a thorough investigation of principles or facts.

## Examples

- He wrote a long treatise on the history of local architecture.
- The professor published a definitive treatise on international law that became a standard text for graduate students.
- The philosopher's final work was a dense treatise exploring the intersection of ethics and aesthetics, challenging centuries of established thought on the nature of beauty.

## Usage notes

- Typically paired with the preposition 'on' to indicate the subject matter.

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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.