nucleus
B2formal
Definition
Meaning
The central and most important part of an object, group, or system; the core.
In biology: the membrane-bound organelle containing genetic material in eukaryotic cells. In physics: the dense central core of an atom, containing protons and neutrons. In astronomy: the central, often brightest part of a galaxy or comet.
Linguistics
Semantic Notes
The word often implies centrality, essentiality, and foundational structure. It suggests the part from which other parts develop or around which they are organised. While the plural is usually 'nuclei', 'nucleuses' is sometimes accepted in non-scientific contexts.
Dialectal Variation
British vs American Usage
Differences
No significant differences in meaning or usage. Pronunciation follows general BrE/AmE patterns for the vowels.
Connotations
Slightly more formal/technical in general use in both varieties. No difference in connotation.
Frequency
Equally frequent in academic/technical contexts. Rare in informal, everyday conversation in both varieties.
Vocabulary
Collocations
Grammar
Valency Patterns
Nucleus of + [noun phrase] (the nucleus of the team)Nucleus + [verb] (The nucleus contains...)Adjective + nucleus (central nucleus)Vocabulary
Synonyms
Strong
Neutral
Weak
Vocabulary
Antonyms
Phrases
Idioms & Phrases
- “[No common idioms directly using 'nucleus']”
Usage
Context Usage
Business
Refers to the small, essential group of key employees or products around which a company is built or expanded. (e.g., 'The management team forms the nucleus of the new division.')
Academic
Standard technical term in biology, physics, and astronomy. Also used metaphorically in social sciences to denote a central principle or founding group.
Everyday
Rare. May be used metaphorically for the central part of a family group or social circle. (e.g., 'My parents are the nucleus of our family.')
Technical
Precise scientific definitions in cell biology (organelle), nuclear physics (atomic structure), and astronomy (galactic/cometary centre).
Examples
By Part of Speech
verb
British English
- The project was nucleated by a small grant from the council.
American English
- The new policy nucleated intense debate among stakeholders.
adverb
British English
- [No standard adverbial form derived directly from 'nucleus']
American English
- [No standard adverbial form derived directly from 'nucleus']
adjective
British English
- The nuclear family structure is evolving.
American English
- Nuclear fission releases immense energy.
Examples
By CEFR Level
- The sun is the nucleus of our solar system.
- The cell nucleus controls the cell's activities.
- A small nucleus of experienced players formed the basis of the new team.
- The research paper posits that the comet's nucleus is primarily composed of ice and dust, with a fragile structure.
Learning
Memory Aids
Mnemonic
Think of a NUT at the CORE of a peach. The NUt-CLEUS is the hard, central, essential part.
Conceptual Metaphor
CENTRE IS IMPORTANCE (The nucleus is the important centre); CONTAINER (The nucleus contains genetic material/particles).
Watch out
Common Pitfalls
Translation Traps (for Russian speakers)
- Do not confuse with 'ядерный' (nuclear) when referring to energy/weapons—'nucleus' is the noun for the central object itself. The adjective 'nuclear' derives from it. The Russian 'ядро' is a good equivalent for the core meaning.
Common Mistakes
- Mispronouncing the plural as 'nucleuses' in scientific contexts (prefer 'nuclei'). Confusing 'nucleus' (the thing) with 'nuclear' (the adjective). Using in overly casual contexts where 'core' or 'centre' would be more natural.
Practice
Quiz
What is the most common plural form of 'nucleus' in scientific English?
FAQ
Frequently Asked Questions
Yes, it is primarily formal and technical. In everyday conversation, words like 'core', 'centre', or 'heart' are more common for metaphorical use.
They are often synonymous in metaphorical use. However, 'nucleus' is the specific, required term in scientific contexts (biology, physics), whereas 'core' is more general and versatile.
Rarely. The verb 'nucleate' exists but is highly technical, mainly used in physics, chemistry, and materials science to describe the formation of a nucleus.
In British English: /ˈnjuː.kli.aɪ/. In American English: /ˈnuː.kli.aɪ/. The stress remains on the first syllable.