An Etymological Dictionary of Astronomy and Astrophysics
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A → chemical element which occurs as a colorless, odorless, and tasteless gas in the atmosphere (of which it constitutes 0.94% by volume) and in some volcanic gases; symbol Ar. → Atomic number 18; → atomic weight 39.948; → melting point -189.2°C; → boiling points -185.7°C.

Argon, from Gk. neutral of argos "inactive, idle, lazy," from negation prefix → a- + ergon "work," → energy. It was discovered in 1895 by the Scottish chemist William Ramsay and the English physicist Robert John Strutt (Lord Rayleigh) in liquified atmospheric air.

A wavelength calibration of astronomical spectra using a helium-argon light source.

→ helium; → argon; → calibration.

A comparison light source containing the known spectral lines of helium and Argon.

→ helium; → argon; → lamp.