As defined by the Hewlett Foundation:
"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."
Creative Commons (CC) licenses differ from traditional copyright in their design and intent.
There are a number of licenses associated with the CC that support OER creation and use.
Each license is chosen by the creator of the product and each license designates how others may (re)use the original creation.
To learn more about choosing licenses visit the Creative Commons.
Depending on the Creative Commons (CC) license of the OER item you're choosing to use, or the license you're assigning to your own creation, there is a sliding scale of use permissions.
The CC-BY license affords the greatest latitude for use while still giving credit where credit is due. CC-BY is highly recommended for OER course material development or use.