The Collaborative International Dictionary of English v.0.48:

Alembic \A*lem"bic\ ([.a]*l[e^]m"b[i^]k), n. [F. alambic (cf.
   Sp. alambique), Ar. al-anb[imac]q, fr. Gr. 'a`mbix cup, cap
   of a still. The cap or head was the alembic proper. Cf.
   Limbec.]
   An apparatus formerly used in distillation, usually made of
   glass or metal. It has mostly given place to the retort and
   worm still.

   Note: Used also metaphorically.

               The alembic of a great poet's imagination.
                                                  --Brimley.
         [1913 Webster]

WordNet (r) 3.0 (2006):

alembic
    n 1: an obsolete kind of container used for distillation; two
         retorts connected by a tube