Source : Webster's Revised Unabridged Dictionary (1913)

Metabasis \Me*tab"a*sis\, n.; pl. {Metabases}. [NL., fr. Gr. ?,
   fr. ? to pass over; ? beyond, over + ? to go.]
   1. (Rhet.) A transition from one subject to another.

   2. (Med.) Same as {Metabola}.