From Middle English flask, flaske (“case, cask, keg”), from Old English flasce, flaxe (“bottle, flask”) and Medieval Latin flascō (“bottle”); from Frankish *flaskā; both from Proto-Germanic *flaskǭ (“braid-covered bottle, wicker-enclosed jug”), from Proto-Indo-European *ploḱ-skō (“flat”), or from Proto-Indo-European *pleḱ- (“to weave”). Doublet of fiasco, flacon, and flagon. Related to Dutch fles; also German Low German Flaske, Fless, German Flasche, Danish flaske; also Lithuanian plókščias, Czech ploský, Albanian flashkët. The sense “laboratory glassware” is from Italian fiasco, and the sense “container for holding a casting mold” is from Middle French flasque (“powder flask”), itself from Old Spanish flasco, frasco, both from Late Latin above.
A narrow-necked vessel of metal or glass, used for various purposes; as of sheet metal, to carry gunpowder in; or of wrought iron, to contain quicksilver; or of glass, to heat water in, etc.
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A container used to discreetly carry a small amount of a hard alcoholic beverage; a pocket flask.
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Sciences Laboratory glassware used to hold larger volumes than test tubes, normally having a narrow mouth of a standard size which widens to a flat or spherical base.
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Engineering, Natural sciences, Physical sciences A container for holding a casting mold, especially for sand casting molds.
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A bed in a gun carriage.
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A nuclear flask, a large, secure lead-lined container for the transport of nuclear material.
Over the years, the railway has been the safest way to move hazardous chemicals, radioactive waste, fuel for Royal Navy nuclear submarines and imported fuel for reprocessing, as well as flasks containing fuel rods to and from British power stations.2023 December 27, Ben Jones, “Inside Sellafield... by rail”, in RAIL, number 999, page 21:
From Middle English flask, flaske (“case, cask, keg”), from Old English flasce, flaxe (“bottle, flask”) and Medieval Latin flascō (“bottle”); from Frankish *flaskā; both from Proto-Germanic *flaskǭ (“braid-covered bottle, wicker-enclosed jug”), from Proto-Indo-European *ploḱ-skō (“flat”), or from Proto-Indo-European *pleḱ- (“to weave”). Doublet of fiasco, flacon, and flagon. Related to Dutch fles; also German Low German Flaske, Fless, German Flasche, Danish flaske; also Lithuanian plókščias, Czech ploský, Albanian flashkët. The sense “laboratory glassware” is from Italian fiasco, and the sense “container for holding a casting mold” is from Middle French flasque (“powder flask”), itself from Old Spanish flasco, frasco, both from Late Latin above.
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Dentistry, Medicine, Sciences To invest a denture in a flask so as to produce a sectional mold.