Helium, e.g (3)
(Other definitions for gas that I've seen before include "Hydrogen possibly" , "Possibly noble" , "Petrol (US)" , "may fill American car" , "chew the fat" .)
(Other definitions for element that I've seen before include "Earth, water, air or fire" , "Fundamental part of whole" , "Component of periodic table" , "Iron, for instance - part of an electric kettle" , "Ideal situation for someone" .)