helium

This term refers to a specific chemical element characterized by its extreme lightness and lack of reactivity. It is most commonly associated with buoyancy and lifting power in a commercial or recreational context, such as in party balloons or weather probes. As a mass noun representing a chemical substance, it does not have a plural form in standard usage. To refer to specific quantities or types of the gas, one must use partitive constructions such as a volume of helium or a sample of helium.