neutron

noun

neu·​tron ˈnü-ˌträn 

ˈnyü-

: 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

neutronic

nü-ˈträ-nik 

nyü-

adjective

Examples of neutron in a Sentence

Recent Examples on the Web

Baryon number can be conserved even when individual protons and neutrons transform into other baryons; what remains unchanged is the total baryon number. — Rupendra Brahambhatt, Interesting Engineering, 16 Aug. 2026

Most potassium atoms are a stable form known as potassium-39, containing 19 protons and 20 neutrons. — Encyclopedia Britannica, 14 Aug. 2026

Hydrogen, which has no neutrons, has roughly double that ratio of any other element, which is why water is often cited as a good space radiation shield. — Jacek Krywko, ArsTechnica, 13 Aug. 2026

The versions of these elements used in the study have the same total number of protons and neutrons combined, but ruthenium has four more protons and four fewer neutrons, making its nucleus more electrically charged. — Joseph Howlett, Scientific American, 13 Aug. 2026

Word History

Etymology

probably from neutral

First Known Use

1921, in the meaning defined above

Phrases Containing neutron

• neutron activation analysis
• neutron bomb
• neutron star

Rhymes for neutron

• anton
• argon
• axon
• baronne
• baryon
• baton
• boron
• buisson
• bygone
• capon
• cardon
• chiffon

Kids Definition

neutron

noun

neu·​tron ˈn(y)ü-ˌträn 

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

Medical Definition

neutron

noun

neu·​tron ˈn(y)ü-ˌträn 

: 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