From 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]