English Reference

Word

neutron

Phoneticsneu·tron

US/ˈnuˌtɹɑn/

UK/njˈuːtɹɒn/

Definition

n. a tiny part of an atom that has no electrical charge. It sits in the center of the atom along with protons.

n. a subatomic particle of about the same mass as a proton but without an electric charge, present in all atomic nuclei except those of ordinary hydrogen.

Examples

“A neutron has no electrical charge.”

“Scientists study how the number of neutrons in an atom's nucleus determines its stability and isotopic identity.”

“The discovery of the neutron allowed physicists to understand why atomic weights were higher than the total mass of the protons alone, leading to the development of modern nuclear models.”

Examples

simple

“A neutron has no electrical charge.”

contextual

“Scientists study how the number of neutrons in an atom's nucleus determines its stability and isotopic identity.”

complex

“The discovery of the neutron allowed physicists to understand why atomic weights were higher than the total mass of the protons alone, leading to the development of modern nuclear models.”

Usage

Commonly used in the plural when discussing atomic structure or nuclear reactions.

Real-World Examples

Common in science and technology writing

“One possible source of damage stems from the production of neutrons, electrically neutral particles released during fusion reactions.”
Phys.org · 15 Aug 2026
“Each type reflects a different way that protons and neutrons reorganize inside a nucleus before releasing gamma rays.”
ScienceDaily · 31 Jul 2026

Etymology

From neutral + -on; by surface analysis, neutr(o)- + -on. Coined by Scottish-Australian physicist William Sutherland in 1899 in a paper in the Philosophical Magazine. Subsequent usage was sporadic and theoretical, sometimes referring to neutrinos rather than neutrons, and the modern sense was reintroduced alongside proton by Ernest Rutherford in 1920.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

Collocations

neutron star

This entry

Level
C1 · Advanced
Frequency
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