Proton is a coordinate term of deuteron.

As nouns the difference between deuteron and proton

is that deuteron is the atomic nucleus of a deuterium atom, consisting of a proton and a neutron while proton is positively charged subatomic particle forming part of the nucleus of an atom and determining the atomic number of an element; the nucleus of the most common isotope of hydrogen; composed of two up quarks and a down quark.