proton

noun pro·ton \ ˈprō-ˌtän \
Updated on: 18 Nov 2017

Definition of proton

: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

play \prō-ˈtä-nik\ adjective

Recent Examples of proton from the Web

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

Origin and Etymology of proton

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

Other Chemical Engineering Terms


PROTON Defined for English Language Learners

proton

noun

Definition of proton for English Language Learners

  • physics : a very small particle of matter that is part of the nucleus of an atom and that has a positive electrical charge


PROTON Defined for Kids

proton

noun pro·ton \ ˈprō-ˌtän \

Definition of proton for Students

:a very small particle that exists in the nucleus of every atom and has a positive charge of electricity

Medical Dictionary

proton

noun pro·ton \ ˈprō-ˌtän \

medical Definition of proton

: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

play \prō-ˈtän-ik\ adjective


Seen and Heard

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

Love words? Need even more definitions?

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

WORD OF THE DAY

to buzz or drone

Get Word of the Day daily email!

Test Your Vocabulary

Find the Cousins

  • a-large-tree-with-many-branches
  • Which pair shares a common word ancestor?
True or False

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

TAKE THE QUIZ
Word Winder's CrossWinder

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

TAKE THE QUIZ

Love words? Need even more definitions?

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