Defining the "Open" in Open Content
"Open content" is content that is licensed in a manner that provides users with the right to make more kinds of uses than those normally permitted under the law. These permissions are granted to users free of charge.
The primary permissions or usage rights open content is concerned with are expressed in the "5Rs Framework:"
Content is open to the extent that its license allows users to engage in the 5R activities. Content is less open to the extent that its license places restrictions (e.g., forbidding derivatives or prohibiting commercial use) or requirements (e.g., mandating that derivatives adopt a certain license or demanding attribution to the original author) on a user's ability to engage in the 5R activities.