A gaseous element present in minute amounts in the atmosphere (0.000524% of dry volume); atomic no. 2, atomic wt. 4.002602; used as a diluent of medicinal gases; used as a diluent of oxygen principally in nonmedical applications, and in its liquid form as the coolant for super-conducting magnets (as in magnetic resonance imaging). [G. helios, the sun]
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he·li·um 'hē-lē-əm n a light colorless nonflammable gaseous element found esp. in natural gases and used chiefly for inflating airships and balloons, for filling incandescent lamps, and for cryogenic research symbol He see ELEMENT (table)
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he·li·um (He) (heґle-əm) [Gr. hēlios sun] a colorless, odorless, tasteless gas, which is not combustible and does not support combustion. It is one of the inert gaseous elements, which was first detected in the sun and is now obtained from natural gas. Atomic number, 2; atomic weight, 4.003. Used in medicine [USP] as a diluent for other gases, being especially useful with oxygen in the treatment of certain cases of respiratory obstruction, and as a vehicle for general anesthetics.Medical dictionary. 2011.