An Etymological Dictionary of the German Language/Annotated/Flasche
Flasche, feminine, ‘bottle, flask,’ from the equivalent Middle High German vlasche, Old High German flasca, feminine (Middle High German also vlesche with mutation); compare Dutch flesch, Anglo-Saxon flasce, feminine, English flask, Old Icelandic (found early) flaska, feminine, Gothic *flaskô, whence Finnish lasku. The word is recorded in Teutonic at an early period, but on account of its correspondence with the Romance words for ‘bottle,’ it may have been borrowed; compare Middle Latin flasco (occurs very early), Italian fiasco, Modern French flacon. Some etymologists derive Middle Latin flasco from Latin vasculum. An exhaustive history of these cognates has not yet been attempted.