helium

/ˈhiliəm/

/ˈhiliəm/

The element helium is a colorless, odorless gas. Because helium is lighter than air, it's commonly used for filling balloons to make them float.

Because of the effect that helium has when lightweight objects are filled with it — making party balloons and parade floats hover in the air as if by magic — it's one of the best-known elements. Helium is almost always a gas, unless it's subjected to very extreme conditions, and it's been used at various times in military airships and weather balloons. The word helium comes from a Greek root, helios, or "sun," because it was initially discovered in the sun's spectrum.

Definitions of helium

1. noun

   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)
   synonyms: He, atomic number 2

   type of:

   chemical element, element

   any of the more than 100 known substances (of which 92 occur naturally) that cannot be separated into simpler substances and that singly or in combination constitute all matter

   argonon, inert gas, noble gas

   any of the chemically inert gaseous elements of the helium group in the periodic table