"Open Educational Resources (OER) are teaching, learning, and research resources that reside in the public domain or have been released under an intellectual property license that permits their free use and re-purposing by others. Open educational resources include full courses, course materials, modules, textbooks, streaming videos, tests, software, and any other tools, materials, or techniques used to support access to knowledge." (http://www.hewlett.org/strategy/open-educational-resources/)
For more information, check out this EDUCAUSE article: "Seven things you should know about Open Educational Resources"
Creative Commons (CC) Licenses enable copyright holders to provide preemptive permission for certain uses. There are six different CC licenses composed of various rights and restrictions. All of the CC licenses require attribution, and best practices for attribution are provided.
"Creative Commons Licenses Explained" by MaconEastLibraryProject is licensed under CC BY-SA 3.0