English dictionary, thesaurus, translations & etymology
FreeDict.com
noun

nucleolus

noo-KLEE-uh-luhs
Quiz me More like this

Nucleolus (noun) means a small, rounded structure found inside the nucleus of a cell. Example: “Under the microscope, the nucleolus appeared as a dark, dense spot.”

noun
1
technical A small, rounded structure found inside the nucleus of a cell.
"Under the microscope, the nucleolus appeared as a dark, dense spot."
"Ribosome parts are assembled within the nucleolus."
"The cell's nucleolus was clearly visible after staining."

How to use nucleolus

Learner’s notes

In plain EnglishA nucleolus is a small structure sitting inside a cell's nucleus.

When to use it

This is a technical, scientific term mainly used in biology.

Memory tip

Watch the irregular plural, nucleoli, rather than adding an s.

Trace the full origin ↓
Easily confused with
Common pairings
visible nucleolus conspicuous nucleolus stain the nucleolus
Vocabulary Flow
Build your vocabulary from words like nucleolus.
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
Test yourself on “nucleolus” A quick quiz — meaning, synonyms & usage →

Fill the gap

Can you complete this real example?

Under the microscope, the _____ appeared as a dark, dense spot.

Etymology

The word combines nucleus with the Latin ending -olus, giving a term that essentially means a small nucleus-like body within the cell nucleus.

Origin: English

Rhymes for nucleolus

See all rhymes for nucleolus →

Frequently asked questions

What is a nucleolus?
It is a small, rounded body found inside the nucleus of a cell.
What is the plural of nucleolus?
The plural is nucleoli.
Is nucleolus the same as nucleus?
No, the nucleolus is a structure found within the nucleus, not the nucleus itself.
What is the meaning of nucleolus?
"nucleolus" (noun) means a small, rounded structure found inside the nucleus of a cell.