flask

UK: /ˈflɑːsk/, /ˈflæsk/ US: /flæsk/ ,(flask, fläsk)

WordReference Random House Learner's Dictionary of American English © 2026

flask¹ /flæsk/   n. [countable]

1. a bottle, usually of glass, having a rounded body and a narrow neck.
2. a flat metal or glass bottle for carrying in the pocket.

WordReference Random House Unabridged Dictionary of American English © 2026

flask¹  (flask, fläsk), n. 

1. a bottle, usually of glass, having a rounded body and a narrow neck, used esp. in laboratory experimentation.
2. a flat metal or glass bottle for carrying in the pocket:
   a flask of brandy.
3. Metallurgy an iron container for shipping mercury, holding a standard commercial unit of 76 lb. (34 kg).
4. Metallurgy a container into which sand is rammed around a pattern to form a mold.

• Late Latin flasca, earlier flascō, of uncertain origin, originally; compare Old English flasce, flaxe, Old High German flasca (German flasche); compare flagon
• Anglo-French, Old French flaske
• late Middle English: cask, keg 1375–1425

flask²  (flask, fläsk), n. [Ordn.]

1. the armored plates making up the sides of a gun-carriage trail.
2. [Obs.] the bed of a gun carriage.

• Late Latin flasca flask¹
• dialect, dialectal French flasque cheek of a gun carriage
• 1570–80

Collins Concise English Dictionary © HarperCollins Publishers::

flask / flɑːsk/ noun

1. a bottle with a narrow neck, esp used in a laboratory or for wine, oil, etc
2. Also called: hip flask a small flattened container of glass or metal designed to be carried in a pocket, esp for liquor
3. See powder flask
4. See vacuum flask

Etymology: 14th Century: from Old French flasque, flaske, from Medieval Latin flasca, flasco, perhaps of Germanic origin; compare Old English flasce, flaxe