- noble gas, inert gas, argonon - any of the chemically inert gaseous elements of the helium group in the periodic table
--1 is a kind of chemical element, element; gas
--1 has particulars:argon, Ar, atomic number 18; helium, He, atomic number 2; krypton, Kr, atomic number 36; neon, Ne, atomic number 10; radon, Rn, atomic number 86; xenon, Xe, atomic number 54