A use of public sector information usually by third persons for purposes other than initial purposes within the public tasks for which data were originally collected, produced, or disseminated. It is rare that data gathered for a particular purpose does not have other possible uses. Once gathered, for whatever reason, data can be re-used again and again, in ways that were never envisaged when it was collected, provided only that the data-holder makes it available under an open licence to enable such re-use. Under the EU OD Directive, data can be re-used for both commercial and non-commercial purposes. An exchange of documents between public sector bodies is not considered to be a re-use of public sector information. 

Sources: ODH, OD Directive