proton
/ˈpɹoʊ.tɑn/ noun C1- A positively charged subatomic particle forming part of the nucleus of an atom and determining the atomic number of an element, composed of two up quarks and a down quark.
- The atomic nucleus of protium (hydrogen-1)
Plural protons
Learn proton in real texts
With a free account, hover any word in the library for its meaning, hear it read aloud, save words for review timed to your memory, and see how much of each book you already know.