Abstract The ambiguity and polysemy of the concept of sustainability is a problem often faced by researchers. The existence of definitions that are not operative, diverse and sometimes contradictory represents a difficulty for the election of a suitable concept of sustainability. Even most of the research works whose title includes the term sustainability do not define what it is, which eventually, constitutes a methodological error. This leads the researchers to avoid defining sustainability, or to study it indirectly through the study of social and ecological variables of certain systems. The present work analysed the meanings conveyed by the concept of sustainability according to researchers. The uses that researchers make of the term sustainability were employed to reveal such meanings. Four uses were identified, which allowed the identification of four meanings of the concept of sustainability. This concluded that the meanings of the concept of sustainability are neither many nor as ambiguous as other authors point out, and that this classification of uses and meanings could be employed to avoid frequent errors made by researchers.