Open Educational Resources (OER) are any type of educational material that is freely available for faculty and students to use, adapt, share, and reuse. Examples of OER include learning content (lesson plans, assignments, textbooks, exams, and videos) as well as tools for learning (software for creating videos and websites and training materials).
Research about Student Learning/Engagement and OERs:
Most OER content is released under a public license, thus you do not have to seek additional permission from the rightsholder in order to do the things authorized by the license. However, you do still need to follow the license terms. For example, the license may require attribution to the original author or it may forbid commercial uses. Other public licenses include the licenses on the lists of free software licenses maintained by the Free Software Foundation and the licenses approved by the Open Source Initiative.
The following descriptions of the Creative Commons licenses come from About the Licenses by Creative Commons and are licensed under a Creative Commons Attribution 4.0 International license.