According to Kuhn (1962), the theoretical terms of two competing theories are incommensurable in the sense that there do not exist logical or conceptual translation relations between them. I call this kind of incommensurability Kuhn-incommensurability. This thesis of Kuhn is supported by the standard analysis of theories in philosophy of science. According to this analysis, the nonlogical terms of a scientific theory T divide into two classes: the so-called non-T-theoretical terms whose meaning is independently given, and the so-called T-theoretical terms, whose meaning is not independently given, but is specified by the theory T itself. For example, time, position and its derivatives w.r.t. (with respect to) time are non-theoretical, while mass and force are theoretical in classical mechanics. It follows from the standard analysis that the meaning of mass and force in classical mechanics is different from their meaning in special relativity theory. The two theories are Kuhn-incommensurable w.r.t. mass and force.