The proton is a nucleon that Ernest Rutherford discovered in 1918 when he noticed that after shooting alpha particles into nitrogen gas, scintillation detectors indicated hydrogen nuclei signatures. Rutherford resolved that 
this hydrogen could only have come from nitrogen; hence nitrogen must consist of hydrogen nuclei. He further suggested that this hydrogen nucleus, known to contain atomic number 1 (elementary particle) should be named proton. Ernest Rutherford is thus usually credited with the discovery of the proton this common reference to him, ‘father of nuclear physics’.
Ernest Rutherford discovered that atoms and nucleuses comprise charges particles, but after discovering the proton, he started shooting alpha particles towards neon particles and after creating the hydrogen element, he reasoned that this basic particle must be among those building blocks of life and atoms. In his experiment, each time an atom was transmuted with another; this process resulted in the emission of hydrogen nuclei. It was thus clear that in the atomic structure, hydrogen nucleus plays an essential role.
Rutherford seemingly coined the terminology proton despite the presence of other physicists working with him. Neutrons and protons are nucleons, which are capable of being bound by nuclear force and converted to atomic nuclei. A proton containing no neutrons is generally a nucleus of a common hydrogen atom isotope.