Open Educational Resources are teaching, learning and research materials in any medium - digital or otherwise - that reside in the public domain or have been released under an open license that permits no-cost access, use, adaptation, and redistributions by others with no or limited restrictions. (From The Flora and William Hewlett Foundation, "Open Educational Resources")
Open Educational Resources are NOT the same as information found on the open web. In addition to being completely free for users, Open Educational Resources must be appropriately licensed for others to use them. Most OERs are licensed under a Creative Commons License, and most permit modification as well as reuse.
The terms "open content" and "open educational resources" describe any copyrightable work (traditionally excluding software, which is described by other terms like "open source") that is either (1) in the public domain or (2) licensed in a manner that provides everyone with free and perpetual permission to engage in the 5R activities:
From David Wiley, "Defining the 'Open' in Open Content and Open Educational Resources"
Three pillars of Open Educational Resources are the legal provisions and provide the basis for using materials in the creation of open educational resources:
Evaluate OER materials by using the following resources:
How to adapt and create Open Educational Resources: