Open Educational Resources (OER), which are teaching, learning, and research resources that are free of cost and access barriers, and which also carry legal permission for open use.* They include a multitude of formats, including textbooks, full courses, modules, videos, labs, assignments, and assessments.
OERs are licensed in such a way that enables adopters to utilize the 5 Rs:
Creative Commons licenses are often applied to OERs to license these rights to adopters.