Source : Webster's Revised Unabridged Dictionary (1913)

Metheglin \Me*theg"lin\, n. [W. meddyglyn; medd mead + llyn
   liquor, juice. See {Mead} a drink.]
   A fermented beverage made of honey and water; mead. --Gay.

Source : WordNet®

metheglin
     n : spiced or medicated mead