Helium (noun)

1. A colorless, odorless, tasteless, non-toxic, inert monatomic gas that heads the noble gas series in the periodic table. Its boiling and melting points are the lowest among all the elements.
2. A gas that is used in balloons and blimps to make them float, and in gas chromatography and gas lasers.

Origin:

From greek "helios" meaning sun.

Examples:

1. Helium is the second lightest element and is present at about 24% of the total elemental mass, which is more than 12 times the mass of all the heavier elements combined.
2. The use of helium in cryogenics, where its low boiling point enables it to be used to cool materials to very low temperatures.
3. Helium is used in gas chromatography and in gas lasers for spectroscopy and in welding and cutting.
4. Helium-filled balloons are popular at children's parties and outdoor events.
5. The use of helium in deep-sea diving, where it is mixed with oxygen to create a breathing gas that reduces the risk of the bends.