Image by Open Scotland is licensed under CC BY 4.0
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.
OER are licensed in such a way that enables adopters to utilize the 5 Rs:
Creative Commons licenses are often applied to OER to license these rights to adopters.