Entity
Webster's Dictionary [1]
(n.) A real being, whether in thought (as an ideal conception) or in fact; being; essence; existence.
Cyclopedia of Biblical, Theological and Ecclesiastical Literature [2]
(entitas), "in the scholastic philosophy, was synonymous with essence or form. To all individuals of a species there is something in conmmon — a nature which transiently invests all, but belongs exclusively to none. This essence, taken by itself and viewed apart from any individual, was what the scholastics called an entity. It denoted the common nature of the individuals of a species or genus. It was the idea or model according to which we conceived of them. The question whether there was a reality corresponding to this idea divided philosophers into Nominalists and Realists (q.v.). Entity is also used to denote anything that exists, as an object of sense or of thought. (See Ens)." — Fleming, Vocabulary Of Philosophy, page 162.