The “real” and the “actual” are often used synonymously and the general term “reality” applied to both. But they were distinct concepts originally and in the course of history, though as central philosophical terms not readily definable.

In medieval terminology, realitas was one of the transcendentals convertible with entity, unity, goodness, etc. It means that anything which has being in any sense at all has a concrete content, determination and essential constitution (see St. Thomas Aquinas, De Veritate, 1, 1 c : “nomen rei exprimit quidditatem sive essentiam entis”; cf. 1 Sententi…