Enabling the interoperability between applications requires agreement in the format and meaning (syntax and semantics) of exchanged data including the ordering of message exchanges. However, today's researchers argue that these are not enough to achieve a complete, effective and meaningful collaboration - the use of data (pragmatics) is important as well. Pragmatic interoperability requires mutual understanding in the use of data between collaborating systems. However, we observe that the notion of pragmatic interoperability is still largely unsettled, as evidenced by the various proposed definitions and the lack of a canonical understanding. Therefore, our objective is to contribute to a more thorough understanding of this concept through a systematic review of published definitions. Our results show that, indeed, various interpretations of pragmatic interoperability exist. Categorizing the derivable concepts from these definitions, we see two broad groups: system level and business level. Within each of these individual levels, we see some degree of agreement among the definitions. However, comparing the definitions across these levels, we observe no general agreement. At the system level, pragmatic interoperability essentially means sharing the same understanding of the intended and actual use of exchanged system message in a given context. At the business level, pragmatic interoperability goes beyond service use by considering also the compatibility of business intentions, business rules, organizational policies, and the establishment and maintenance of trust and reputation mechanisms between collaborating business parties.