Source : Webster's Revised Unabridged Dictionary (1913)

Flask \Flask\, n. [AS. flasce, flaxe; akin to D. flesch, OHG.
   flasca, G. flasche, Icel. & Sw. flaska, Dan. flaske, OF.
   flasche, LL. flasca, flasco; of uncertain origin; cf. L.
   vasculum, dim. of vas a vessel, Gr. ?, ?, ?. Cf. {Flagon},
   {Flasket}.]
   1. A small bottle-shaped vessel for holding fluids; as, a
      flask of oil or wine.

   2. 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.

   3. A bed in a gun carriage. [Obs.] --Bailey.

   4. (Founding) The wooden or iron frame which holds the sand,
      etc., forming the mold used in a foundry; it consists of
      two or more parts; viz., the cope or top; sometimes, the
      cheeks, or middle part; and the drag, or bottom part. When
      there are one or more cheeks, the flask is called a three
      part flask, four part flask, etc.

   {Erlenmeyer flask}, a thin glass flask, flat-bottomed and
      cone-shaped to allow of safely shaking its contents
      laterally without danger of spilling; -- so called from
      Erlenmeyer, a German chemist who invented it.

   {Florence flask}. [From Florence in Italy.]
      (a) Same as {Betty}, n., 3.
      (b) A glass flask, round or pear-shaped, with round or
          flat bottom, and usually very thin to allow of heating
          solutions.

   {Pocket flask}, a kind of pocket dram bottle, often covered
      with metal or leather to protect it from breaking.

Source : WordNet®

flask
     n 1: bottle that has a narrow neck
     2: the quantity a flask will hold [syn: {flaskful}]