n.
Pronunciation: ' pr ō - ˌ tän
Function: noun
Etymology: Greek pr ō ton, neuter of pr ō tos first ― more at PROT-
Date: 1920
: 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
– pro · ton · ic \ pr ō - ' tä-nik \ adjective