A colorless, odorless, tasteless, nearly inert noble gas with the symbol He and atomic number 2. It is after hydrogen the second most abundant element in the universe. It is a component of air and is being used for balloon and airship fillings, as well as for deep-sea breathing systems in combination with oxygen.
a very light colorless element that is one of the six inert gasses; the most difficult gas to liquefy; occurs in economically extractable amounts in certain natural gases (as those found in Texas and Kansas)
