Source : Webster's Revised Unabridged Dictionary (1913)

Flagon \Flag"on\, n. [F. flacon, for flascon, fr. OF. flasche,
   from LL. flasco. See {Flask}.]
   A vessel with a narrow mouth, used for holding and conveying
   liquors. It is generally larger than a bottle, and of leather
   or stoneware rather than of glass.

         A trencher of mutton chops, and a flagon of ale.
                                                  --Macaulay.

Source : WordNet®

flagon
     n : a large metal or pottery vessel with a handle and spout;
         used to hold alcoholic beverages (usually wine)