‘Open knowledge’ is any content, information or data that people are free to use, re-use and redistribute — without any legal, technological or social restriction. We detail exactly what openness entails in the Open Knowledge Definition. The main principles are: Free and open access to the material Freedom to redistribute the material Freedom to reuse the material No restriction of the above based on who someone is (e.g. their nationality) or their field of endeavour (e.g. commercial or non-commercial).