proton

noun

pro·​ton ˈprō-ˌtän 

: an elementary particle that is identical with the nucleus of the hydrogen atom, that along with the neutron is a constituent of all other atomic nuclei, that carries a positive charge numerically equal to the charge of an electron, and that has a mass of 1.673 × 10⁻²⁷ kilogram

protonic

prō-ˈtä-nik 

adjective

Examples of proton in a Sentence

Recent Examples on the Web

The protease partially pulls a proton off the water molecule, activating it to attack and break up the peptide bond. — ArsTechnica, 14 Oct. 2026

Hydrogen is the simplest element on the periodic table, with one proton and one electron. — Jijo Malayil, Interesting Engineering, 9 Oct. 2026

Neutrinos hint at where cosmic rays come from Every second, more than 10,000 high-energy particles – protons and atomic nuclei – rain down from space on every square meter of the Earth’s atmosphere. — Tyce Deyoung, The Conversation, 6 Oct. 2026

Chemical groups on the glycerol, cellulose, and PVP help water release protons (hydrogen ions). — New Atlas, 4 Oct. 2026

Word History

Etymology

Greek prōton, neuter of prōtos first — more at proto-

First Known Use

1920, in the meaning defined above

Phrases Containing proton

• proton pump inhibitor
• proton synchrotron

Rhymes for proton

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

Kids Definition

proton

noun

pro·​ton ˈprō-ˌtän 

: an atomic particle that occurs in the nucleus of every atom and carries a positive charge equal in size to the negative charge of an electron

protonic

prō-ˈtän-ik 

adjective

Medical Definition

proton

noun

pro·​ton ˈprō-ˌtän 

: an elementary particle that is identical with the nucleus of the hydrogen atom, that along with neutrons is a constituent of all other atomic nuclei, that carries a positive charge numerically equal to the charge of an electron, and that has a mass of 1.673×10⁻²⁴ gram

protonic

prō-ˈtän-ik 

adjective