Source : Webster's Revised Unabridged Dictionary (1913)

Ens \Ens\, n. [L., ens, entis, a thing. See {Entity}.]
   1. (Metaph.) Entity, being, or existence; an actually
      existing being; also, God, as the Being of Beings.

   2. (Chem.) Something supposed to condense within itself all
      the virtues and qualities of a substance from which it is
      extracted; essence. [Obs.]

Source : Free On-Line Dictionary of Computing

ENS
     
         See {Ecole Normale Superieure}