What does alkahest mean?
The definition of alkahest
Al”ka*hest, n.
Etym: [LL. alchahest, F. alcahest, a word that has an Arabic appearance, but was probably arbitrarily formed by Paracelsus.]

The fabled “universal solvent” of the alchemists; a menstruum capable of dissolving all bodies.

— Al`ka*hes”tic, a.