Open Educational Resources (OER) are defined as "born digital content made available for free or for a nominal fee in a range of formats, including textbooks, games, media, and instructional readings. OER are freely available online and can be used in learning management systems and accessed multiple times across various devices by an unlimited number of simultaneous users. They can be shared and their content remixed and repurposed by authors and users. Authors of OER materials maintain their rights to their work and use Creative Commons licensing terms or a similar type of agreement to share them."
Source: Okamoto, Karen. "Making Higher Education More Affordable, One Course Reading at a Time: Academic Libraries as Key Advocates for Open Access Textbooks and Educational Resources." Public Services Quarterly 9.4 (2013): 267-283 LISTA. Web. 28 Oct. 2015 opencontent.org/definition
See also: Resources at SUNY OER Services
A useful way to appreciate the value of OER is to understand what you, the user of openly licensed content, are allowed to do with it. These permissions are granted in advance, and are legally established through Public Domain or Creative Commons copyrights:
This material is from SUNY OER Services, which is available at https://online.suny.edu/sunyoercommunitycourse/understanding-oer/defining-oer This material is adapted from original writing by David Wiley, which was published freely under a Creative Commons Attribution 4.0 license at http://opencontent.org/definition/.
Read more about open rights on the SUNY Oneonta Copyright and Creative Commons page.