“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.”
Definition from the The William and Flora Hewlett Foundation

And how can we use them?

• Retain – Make and own a copy
• Reuse – Use in a wide range of ways
• Revise – Adapt, modify, and improve
• Remix – Combine two or more
• Redistribute – Share with others