Etymology [ flask, fl[a]sk ] (noun.) 1549. From Middle English flask (“cask, keg”), from flaske (“case”), from Anglo-Norman flaske (subject case), flascon (object case), from Late Latin flascō ‘bottle’, from Frankish *flasko (cf. Dutch (Flemish) vlesch), from Proto-Germanic *flaskōn ‘braid-covered bottle, wicker-enclosed jug’ (cf. Old English flaxe, flasce, West Frisian flesse, German Flasche), from Proto-Indo-European *plok̑-skō (cf. Lithuanian plókščias (“flat”), Old Church Slavonic ploskŭ (“flat”)).
Sense 2 from Italian fiasco and sense 3 from Middle French flasque (“powder flask”), itself from Old Spanish flasco, frasco, all words being of the same origin as above.
Synonyms alembic, ampulla, bag, beaker, bottle, canteen, carafe, caster, chalice, crock, cruet, crystal, decanter, demijohn, ewer, fiasco, flacon, flagon, flasket, glass