It was though, at least for me it is after the exercise where this kind of "aus" was taught
I think "Flasche" is a cognate for "flask." They sound like they come from the same roots. The reason it's translated as "bottle" is most likely because we use "bottle" most frequently and in the same way that they use "Flasche."
I confirm, the word has the same root in many languages.
Flask - English Flasche - German Flaska - Hungarian
These are 3 languages I know, could be more. :p
We have fiasco and fiaschetta in Italian. :D
But the main word for bottle is bottiglia. :)