noun
: a positively charged nuclear particle identical with the nucleus of a helium atom, consisting of 2 protons and 2 neutrons, having atomic mass 4 and atomic number 2, ejected at high speed in certain radioactive transformations
noun
: a positively charged nuclear particle identical with the nucleus of a helium atom, consisting of 2 protons and 2 neutrons, having atomic mass 4 and atomic number 2, ejected at high speed in certain radioactive transformations
Webster's New International English Dictionary. Новый международный словарь английского языка Webster. 2012