argon

Estimated CEFR level: C2 — Proficiency

Estimated from word frequency; not an official CEFR classification.

Definition

noun a colorless and odorless inert gas; one of the six inert gases; comprises approximately 1% of the earth's atmosphere

From Ancient Greek ἀργός (argós, “idle, lazy”), because of its inertness, + -on, used for all noble gases.

Spectrum analysis of the black powder points unmistakably to the presence of an unknown element with a brilliant group of three lines in the green, and it is possible that it combines with argon to form a compound which acts at once with deadly effect upon some constituent in the blood. — The war of the worlds, H. G. (Herbert George) Wells

Ar, atomic number 18

Type a word, a sentence, a book title, or a link to an English article. WordNet and the Classics answer.

Try

A library of classics · a vault of words · instant etymology & meaning