What are open educational resources (OER)?

The University of Edinburgh’s OER Policy defines open educational resources as follows:

learning, teaching and research materials in any format and medium that reside in the public domain or are under copyright that have been released under an open license, that permit no-cost access, re-use, re-purpose, adaptation and redistribution by others. -UNESCO Recommendation on Open Educational Resources (2019)

Open educational resources can take many forms including, but not limited to:

Videos
Images, including graphics, photographs, diagrams, etc
Audio, including podcasts, recorded lectures, music
Web pages
Text documents, including Word documents, PDFs, articles, book chapters
Open textbooks
Wikipedia articles
Simulations
Data sets
3D models
Xerte objects
Reading lists
Lesson plans
Blogs and blog posts

Further information

Open Educational Resources, UNESCO

Open Educational Resources article on Wikipedia

What is OER? on Creative Commons Wiki

The Cape Town Open Education Declaration

Capetown +10 Ten Directions to Move the Open Education Movement Forward

Open Education and OER: A guide and call to action for policy makers, Association for Learning Technology