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

For months before today’s launch, Google has been anticipating those problems on Earth, shaking spacecraft to simulate the launch and bombarding its chips with proton beams to test their response to radiation. — Peter Hall, Scientific American, 1 Oct. 2026

The process generated large numbers of energetic, or fast, protons in the plasma. — Georgina Jedikovska, Interesting Engineering, 30 Sep. 2026

What followed was an awake brain surgery, 33 rounds of proton radiation, chemotherapy, medications, scans, bloodwork, and a new, unrelenting relationship with my body and mind. — Stefanie Benjamin, Travel + Leisure, 26 Sep. 2026

Neutrons are unstable when they’re not bound in nuclei, spontaneously spitting out lighter particles in about 15 minutes to become the slightly lighter proton. — Cara Giovanetti, The Conversation, 25 Sep. 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