- The definition of a proton is a particle with a positive charge that is in the nucleus of an atom.
An example of a proton is the single proton in the nucleus of a hydrogen atom.
Particle Physics a nucleon carrying a positive charge equal to the negative charge of an electron and having a mass of c. 1.673 × 10kg (c. 938.2796 MeV/c, c. 1,836 times the mass of an electron): the number of protons in an atom determines the atomic number of a chemical element
Origin of protonModern Latin ; from Classical Greek prōton, neuter of prōtos, first: see proto-
The stable, positively charged nucleon, having a mass 1,836 times that of an electron and being a baryon composed of two up quarks and one down quark. The proton is a basic component of all atomic nuclei and the nucleus of the protium isotope of hydrogen.
Origin of protonFrom Greek prōton, neuter of prōtos, first; see per1 in Indo-European roots.
From Ancient Greek πρῶτον (prōton), neuter of πρῶτος (prōtos, “first”)