neu·​tron | \ ˈnü-ˌträn, ˈnyü-\

Definition of neutron

: an uncharged elementary particle that has a mass nearly equal to that of the proton and is present in all known atomic nuclei except the hydrogen nucleus

Keep scrolling for more

Other Words from neutron

neutronic \ nü-​ˈträ-​nik , nyü-​ \ adjective

Examples of neutron in a Sentence

Recent Examples on the Web

Universes with a weaker weak force would have stars with more deuterium, which is a hydrogen atom with an extra neutron within its nucleus. Charles Q. Choi,, "Why Alternate Universes Might Also Host Life Around their Stars," 26 Sep. 2018 These observations confirmed that these collisions act as factories for heavy, neutron-rich elements that would be difficult to form in supernovae. John Timmer, Ars Technica, "Neutron-star merger blasted a jet of material through the debris," 5 Sep. 2018 These isotopes differ in the number of neutrons in the oxygen atom and, according to MacLeod, behave slightly differently from one another. Tereza Pultarova,, "Dino-Killing Asteroid Impact Warmed Earth's Climate for 100,000 Years," 24 May 2018 The building blocks of atoms, protons and neutrons, are composed of a collection of particles called quarks and gluons. John Timmer, Ars Technica, "Atoms may come apart as the Universe’s biggest stars explode," 24 Oct. 2018 The new results suggest that neutron-star mergers are important sources of short-duration gamma-ray bursts, study team members said. Mike Wall,, "Faster Than Light? Neutron-Star Merger Shot Out a Jet with Seemingly Impossible Speed," 5 Sep. 2018 When this collision occurs, the proton transforms into a neutron and ejects a positron, the antimatter version of an electron. Kenneth Chang, New York Times, "How to Spot a Nuclear Bomb Program? Look for Ghostly Particles," 27 Mar. 2018 Russia has the world's only fast-neutron test reactor. Adrian Cho, Science | AAAS, "Congress pushes for multibillion-dollar nuclear reactor that critics call a boondoggle," 3 July 2018 Most people with a semester of chemistry under their belt understand that atoms are made up of protons, neutrons and electrons. Jason Daley, Smithsonian, "The Large Hadron Collider Is Getting A Huge Power Boost," 19 June 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'neutron.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

See More

First Known Use of neutron

1921, in the meaning defined above

History and Etymology for neutron

probably from neutral

Keep scrolling for more

Learn More about neutron

Statistics for neutron

Last Updated

12 Jan 2019

Look-up Popularity

Time Traveler for neutron

The first known use of neutron was in 1921

See more words from the same year

Keep scrolling for more

More Definitions for neutron



English Language Learners Definition of neutron

physics : a very small particle of matter that has no electrical charge and is part of the nucleus of all atoms except hydrogen atoms


neu·​tron | \ ˈnü-ˌträn, ˈnyü-\

Kids Definition of neutron

: a particle that has a mass nearly equal to that of the proton but no electrical charge and that is present in all atomic nuclei except those of hydrogen


neu·​tron | \ ˈn(y)ü-ˌträn \

Medical Definition of neutron

: an uncharged elementary particle that has a mass nearly equal to that of the proton and is present in all known atomic nuclei except the hydrogen nucleus

Keep scrolling for more

More from Merriam-Webster on neutron

Rhyming Dictionary: Words that rhyme with neutron

Spanish Central: Translation of neutron

Nglish: Translation of neutron for Spanish Speakers Encyclopedia article about neutron

Comments on neutron

What made you want to look up neutron? Please tell us where you read or heard it (including the quote, if possible).


to gather or build up little by little

Get Word of the Day daily email!

Test Your Vocabulary

Homophone Quiz

  • three-bears-two-of-them-look-like-theyre-whispering-to-a-third-bear-who-looks-chuffed-to-be-the-center-of-attention
  • In order to judge how people felt, the senator's office hired a firm to take a ______.
True or False

Test your knowledge - and maybe learn something along the way.


Test Your Knowledge - and learn some interesting things along the way.


Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!