An elementary particle with a positive charge. It’s a part of the nucleus of atoms and the attraction between the protons in the nucleus and the orbiting electrons plays a key role in how tightly bound electrons are to the atom. Despite this, the role of protons in electronics and electrical engineering is basically non-existent. Typically we let physicists and material scientists worry about them.
Particle with positive charge in the nucleus of an atom.
Grob’s Basic Electronics, 11th Edition by Mitchel E. Schultz
The basic particle of positive charge.
Electronic Devices : Conventional Current Version, 9th Edition by Thomas L. Floyd