We should first verify that there are five areas of meaning of the japanese word katte (gatte in tsukaigatte meaning usability). It could mean either (1) "kitchen&sbquo" (2) "condition" or "circumstance&sbquo" (3) "convenience&sbquo" (4) "livelihood&sbquo" "family budget" or "lifestyle&sbquo" and (5) "acting freely for one's own convenience" or "being selfish." The last definition was derived from its old meaning as "archer." Tsukaigatte can be evaluated from the combination of these definitions for katte by considering the balance between how easy it is to use&sbquo the conditions under which it is used&sbquo convenience&sbquo and economical factors. in other words&sbquo the word is used to evaluate both design and functionality at once. In design&sbquo the word tsukaigatte corresponds to "usability&sbquo" but the meaning is usually represented by the word "convenience." The evaluative term tsukaigatte&sbquo however&sbquo relates to the degree to which the object's adaptability and usability in its more practical usage solves a problem. The difference between tsukaigatte and usability is that it's possible that the tsukaigatte can improve as the user gains more experience with the object. In other words&sbquo usability that adapts to the user's frivolous use is not necessarily the result of ideal design providing full functionality. Rather&sbquo building the relationship between design and tsukaigatte in the future will invoLve improving the quality of experience by considering the sensation of using the object. "Usability" is an expression of functionality that improves the quality of such quality of experience.