Open educational resources (OERs) are resources that are part of the public domain, or have been released under a license that permits free use. OERs include learning content such as videos, audio clips, images, lecture notes, reading lists, course assignments, syllabi and lesson plans, textbooks, reports, articles, data, instructional games, tests and quizzes, etc. A broader definition of OER encompasses software tools such as open-source software (course management systems, video and web page editing systems, open operating systems, etc.), as well as implementation resources such as intellectual-property licenses, best-practices documents, and interoperability standards and guidelines.