# theses

/ˈθisiz/ (US) · /θəsˈiːz/ (UK) · CEFR C1 · Noun

Source: https://englishreference.com/word/theses
Updated: 2026-05-07

## Definition

long pieces of writing that students complete at the end of a university degree. They are usually based on original research and used to prove a specific idea.

For teachers: plural form of 'thesis'; refers to long-form academic dissertations involving original research and the defense of a specific proposition.

## Examples

- The students submitted their final theses to the department today.
- The university library keeps a digital archive of all doctoral theses published by its graduates over the last decade.
- While undergraduate essays often summarize existing knowledge, doctoral theses are expected to contribute original insights or novel data to their respective academic fields.

## Pitfalls

- Not "the student's thesises" but "the student's theses" — The word follows Greek pluralization rules; adding '-es' to the singular form is a common error.

## Usage notes

- The plural form of 'thesis', following the Greek-derived pattern where '-is' changes to '-es'.

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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.