As a preliminary step of composing the concept of sport, the meaning and significance of sport as a social institution was discussed through reconsidering J.W. Loy's five papers on sport paradigm. After examining his papers following problems were pointed out. 1) As a criterion of classifying play, game and sport, the dichotomy of competition and physical prowess is too narrow while the institutionalized level is too wide. Since institutional pattern is recognized both in sports and games, it can not be a proper criterion of classifying them. It is not clear that how expressive and instrumental aspects, as well as play and work, of his paradigm are to be integrated and sublated. 2) Loy's definition of institution is still ambiguous. It is used in such various meanings as group, organization, social system, and situation. It should be specified as a norm system. 3) As his theory of sport as an institution excessively emphasizes the negative aspects of reified and alienated sport, his theory based on humanistic views is confined to presuppose pre-established harmony in sport which points up only positive and autonomous aspects. 4) The function of sports should be distinguished from that of sport as an institution, but he confuses them and restricts these functions too narrowly. It was concluded that sport should neither be contrasted with social realities nor be considered to be subsumed by a paramount reality. In order to analyze the simultaneity of the subjective and objective aspects of sports and the expressive and instrumental functions of sport it should conversely be understood that sport is one of the multiple realities and sport constructs a multiple reality in itself.