My concern in this paper is with the meaning of the word 'space" — spatium, der Raum — in Kant's usage. This is not an attempt merely at another exposition of Kant's doctrine of space as transcendentally ideal and empirically real. I want to get at the meaning of the word as Kant understood it. This is worth doing, I suggest, since we tend to approach Kant's theory with a meaning which has become implicit as a result of the virtually complete dominance of the Newtonian inheritance from the early nineteenth century onward. In our time the noun 'space", "der Raum", implicitly carries the connotation of some sort of entity. This was not so with the word spatium — 'space" in English — in its original meaning, which persisted through the seventeenth century. In its original general and basic sense the word meant "an interval, a stretch or extent, between things' — which certainly did not connote an entity. That is, originally spatium, and 'space" in English, was an abstract noun, whereas it later became a concrete noun.