# nuclei

/ˈnukɫiˌaɪ/ (US) · /njˈuːklɪˌi/ (UK) · CEFR C1 · Noun

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

## Definition

the plural form of nucleus. It refers to the central parts of cells or the centers of atoms.

For teachers: the plural of 'nucleus'; refers to the central and most important parts of an object, movement, or group, or the membrane-bound organelles containing genetic material in cells.

## Examples

- Most cells have single nuclei that hold their DNA.
- In physics class, we learned how the nuclei of atoms are held together by the strong nuclear force.
- The researchers observed that certain muscle fibers are multinucleated, meaning they contain multiple nuclei within a single continuous cytoplasm to coordinate protein synthesis across large distances.

## Pitfalls

- Not "The nucleis of the atoms" but "The nuclei of the atoms" — Nuclei is already plural; adding an 's' is a common error based on standard English pluralization rules.

## Usage notes

- The plural form of 'nucleus'. It takes a plural verb agreement ('the nuclei are').

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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.