"There is no one, standard definition of Open Educational Resources. However, the following broad definition of OERs from OER Commons seems to be generally accepted by the community:
Open Educational Resources (OER) are teaching and learning materials that are freely available online for everyone to use, whether you are an instructor, student or self-learner. Examples of OER include: full courses, course modules, syllabi, lectures, homework assignments, quizzes, lab and classroom activities, pedagogical materials, games, simulations, and many more resources contained in digital media collections from around the world.
OERs exist within a wider 'Open' movement and context, explored below."