The Collaborative International Dictionary of English v.0.48:

Ens \Ens\ ([e^]nz), 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.
      [1913 Webster]

   2. (Chem.) Something supposed to condense within itself all
      the virtues and qualities of a substance from which it is
      extracted; essence. [Obs.]
      [1913 Webster]

V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

ENS
       Enterprise Network Services (Banyan, VINES)


The Free On-line Dictionary of Computing (30 December 2018):

ENS

    See Ecole Normale Superieure