nucleus
NYOO-klee-uhs
Nucleus (noun) means the central, positively charged part of an atom, made of protons and neutrons. Example: “Electrons orbit the nucleus of an atom.”
noun
1
The central, positively charged part of an atom, made of protons and neutrons.
"Electrons orbit the nucleus of an atom."
"A single proton can form the nucleus of a hydrogen atom."
"The teacher drew a small circle to show the nucleus, with electrons around it."
2
The core part of something around which everything else is built.
"These five players formed the nucleus of the championship team."
"A few close friends formed the nucleus of the new book club."
"The old town centre became the nucleus around which the city grew."
3
The membrane-bound structure in a cell that holds its genetic material.
"Under the microscope, the cell's nucleus stained dark blue."
"DNA is stored inside the nucleus of most human cells."
"The student labelled the nucleus on her diagram of an animal cell."
How to use nucleus
Learner’s notesIn plain EnglishThe central core of something — whether an atom, a cell, or a group.
Common pairings
atomic nucleus
cell nucleus
nucleus of a team
Vocabulary Flow
Build your vocabulary from words like nucleus.
Vocabulary Flow serves the next word, and the next — meaning, pronunciation and an example each time. Practice at your level, or learn English in your own language.
Start vocabulary practice
Word forms
- Plural
- nuclei, nucleuses
Fill the gap
Can you complete this real example?
Electrons orbit the _____ of an atom.
Etymology
A learned borrowing from Latin nucleus, "kernel" or "core."
Related words
Rhymes for nucleus
See all rhymes for nucleus →Frequently asked questions
What does “nucleus” mean?
The word “nucleus” means the central, positively charged part of an atom, made of protons and neutrons. In plain terms, the central core of something — whether an atom, a cell, or a group.
How do you pronounce “nucleus”?
“Nucleus” is pronounced NYOO-klee-uhs (/ˈnuː.kli.əs/ in IPA).
How do you use “nucleus” in a sentence?
Here is “nucleus” used in a sentence: “Electrons orbit the nucleus of an atom.”
What part of speech is “nucleus”?
“Nucleus” is a noun.
Where does the word “nucleus” come from?
The word “nucleus” comes from Latin. A learned borrowing from Latin nucleus, "kernel" or "core.".
Is “nucleus” a common word?
“Nucleus” is an uncommon word in modern English, usually learned at around the B1 level.
How many meanings does “nucleus” have?
“Nucleus” has 3 distinct senses listed in this dictionary. The most common is: the central, positively charged part of an atom, made of protons and neutrons.
What is the difference between the nucleus of an atom and the nucleus of a cell?
The nucleus of an atom is the central, positively charged core made of protons and neutrons, and it is the seat of an atom's mass and charge. The nucleus of a cell is a completely different structure: a membrane-bound compartment that holds the cell's genetic material. The two share only the name, referring to a central core in very different scientific contexts.
Can nucleus be used outside of science?
Yes, nucleus is often used figuratively to describe the core part of something around which everything else is built, such as 'the nucleus of a new team' or 'the nucleus of an idea.' In this sense it means the central, foundational element rather than anything biological or physical.
What is the plural of nucleus?
The traditional plural is nuclei, following the word's Latin origin, though nucleuses is also used informally in English. Nuclei remains the standard form in scientific and academic writing.
Featured in
Vocabulary lists that include nucleus:
