Flask meaning : A narrow-necked vessel of metal or glass, used for various purposes; as of sheet metal, to carry gunpowder in; or of wrought iron, to contain quicksilver; or of glass, to heat water in, etc. A container used to discreetly carry a small amount of a hard alcoholic beverage; a pocket flask. Laboratory glassware used to hold larger volumes than test tubes, normally having a narrow mouth of a standard size which widens to a flat or spherical base. A container for holding a casting mold, especially for sand casting molds. A bed in a gun carriage. To invest a denture in a flask so as to produce a sectional mold.