a colorless, odorless chemical element, one of the noble gases, having the lowest known boiling and melting points: it is used in low-temperature work, as a diluent for oxygen, in deep-sea breathing systems, for inflating balloons, etc.: symbol, He; at. no. 2
Origin of heliumModern Latin from Classical Greek h?lios: see Helios
A colorless, odorless inert gaseous element occurring in natural gas and with radioactive ores. It is used as a component of artificial atmospheres and laser media, as a refrigerant, as a lifting gas for balloons, and as a superfluid in cryogenic research. Atomic number 2; atomic weight 4.0026; boiling point −268.9°C; density at 0°C 0.1785 gram per liter. See Periodic Table.
Origin of heliumFrom Greek hēlios sun (so called because its existence was deduced from the solar spectrum) ; see sāwel- in Indo-European roots.
(countable and uncountable, plural heliums)
From New Latin helium, from Ancient Greek ἥλιος (hēlios, “sun”) (because its presence was first theorised in the sun's atmosphere).