Lewis & Short

* ens, entis, n. [sum], a thing; formed, like essentia, after the Gr. οὐσία, by Flavius (or Fabianus), acc. to Quint. 8, 3, 33 Spald. N. cr., but first used by Caesar, acc. to Prisc. 18, 8, 75: entia (= τὰὄντα), Quint. 2, 14, 2.