Open Educational Resources (OER) are teaching, learning, and research materials that are either in public domain or licensed in a manner that provides everyone with free and perpetual permission to engage in the 5R activities:
Retain – make, own, and control a copy of the resource
Reuse – use your original, revised, or remixed copy of resource publicly
Revise – edit, adapt, and modify your copy of the resource
Remix – combine your original and revised copy of the resource with other existing material to create something new
Redistribute – share copes of your original, revised, or remixed copy of resources with others