The Collaborative International Dictionary of English v.0.48:

Aludel \Al"u*del\, n. [F. & Sp. aludel, fr. Ar. aluth[=a]l.]
   (Chem.)
   One of the pear-shaped pots open at both ends, and so formed
   as to be fitted together, the neck of one into the bottom of
   another in succession; -- used in the process of sublimation.
   --Ure.
   [1913 Webster]