HELIUM-4 Meaning of HELIUM-4 in English ¦ ̷ ̷ ̷ ̷ ̷ ̷ ˈ ̷ ̷ nounEtymology: helium + 4 , mass number of the isotope: helium Webster's New International English Dictionary. Новый международный словарь английского языка Webster. 2012