argon(redirected from Element 18)
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n. Symbol Ar
A colorless, odorless, inert gaseous element constituting approximately one percent of the earth's atmosphere, from which it is commercially obtained by fractionation for use in electric light bulbs, fluorescent tubes, and radio vacuum tubes and as an inert gas shield in arc welding. Atomic number 18; atomic weight 39.948; melting point -189.36°C; boiling point -185.85°C. See Periodic Table.
(Elements & Compounds) an extremely unreactive colourless odourless element of the rare gas series that forms almost 1 per cent (by volume) of the atmosphere. It is used in electric lights. Symbol: Ar; atomic no: 18; atomic wt: 39.948; density: 1.7837 kg/m3; freezing pt: –189.3°C; boiling pt: –185.9°C
[C19: from Greek, from argos idle, inactive, from a-1 + ergon work]
a colorless, odorless, chemically inactive, monatomic, gaseous element that is used for filling fluorescent and incandescent lamps and vacuum tubes. Symbol: Ar; at. no.: 18; at. wt.: 39.948.
[1890–95; < Greek, neuter of argós inactive, idle, contraction of aergós]
Symbol Ar A colorless, odorless element that is a noble gas and makes up about one percent of the atmosphere. It is used in electric light bulbs, fluorescent tubes, and radio vacuum tubes. Atomic number 18. See Periodic Table.
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|Noun||1.||argon - a colorless and odorless inert gas; one of the six inert gases; comprises approximately 1% of the earth's atmosphere|
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
air - a mixture of gases (especially oxygen) required for breathing; the stuff that the wind consists of; "air pollution"; "a smell of chemicals in the air"; "open a window and let in some air"; "I need some fresh air"