Source : Webster's Revised Unabridged Dictionary (1913)

Demijohn \Dem"i*john\, n. [F. dame-jeanne, i.e., Lady Jane, a
   corruption of Ar. damaj[=a]na, damj[=a]na, prob. fr. Damaghan
   a town in the Persian province of Khorassan, once famous for
   its glass works.]
   A glass vessel or bottle with a large body and small neck,
   inclosed in wickerwork.

Source : WordNet®

demijohn
     n : large bottle with a short narrow neck; often has small
         handles at neck and is enclosed in wickerwork