a conical or, spherical, etc narrow-necked usu glass container with a narrow neck used for wine or in a laboratory
a broad flat bottle, usu of metal or leather-covered glass, used to carry alcohol or other drinks on the person; = hip flask
= vacuum flask
a lead-lined container for nuclear waste
[Middle English flasce cask, from late Latin flasca, flasco, prob of Germanic origin, the sense ‘glass container’ arriving in the late 17th cent., influenced by Italian fiasco bottle]