Longman Dictionary of Contemporary English homepage

Date: 1800-1900
Language: Greek
Origin: 'first thing', from protos; PROTO-

proton

 noun
     
Related topics: Physics
pro‧ton [countable]
HP a very small piece of matter with a positive electrical charge that is in the central part of an atom [↪ electron, neutron]
Definition from the Longman Dictionary of Contemporary English
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