The title, of this paper as taken from Machlup (1967, 3-6) who argues that semantic issues have been debated by those undertaking economic research at least since the time of Malthus. As Machlup(1907, 6) further argues, although semantic exercises should not substitute for substantive research, semantic clarification is a necessary condition for successful research. The purpose of this paper is to examine the various meanings of the footloose industry concept employed in the regional science and economic geography literature. We find that the footloose concept has been used in various (sometimes contradictory) ways and, in addition, that the various locational criteria found in the footloose literature have frequently been defined in the literature independently of' the footloose concept. Different usages by different writers impede effective communication among researchers investigating industry location decisions. The vagueness and ambiguity of the footloose industry concept may also lead to communication-based errors by policy-makers. Conner (1986,10) states, 'The ongoing state and regional economic development programmes are likely to have the greatest impact on industrial location for ... 'foot-loose' industries.' Yet what is a footloose industry; and what determines its locational choice?