A license is official permission for authorized use. For example, you may have a license to play music from iTunes, or to stream movies from Netflix. Similarly, you can have a license to read articles from library databases. This doesn't mean that you own the movies from Netflix or the articles from the library. It means you have a license to use these works.
Creative Commons is an organization that has created a set of international licenses that allow creators to give permission to people to use their work. Here's a guide to the Creative Commons licenses and symbols.
Creative Commons (CC): This is the basic symbol that says you are using a Creatives Commons license, and you can use the work without asking for permission.
Attribution (BY): This symbol means the owner wants to be attributed, or credited, for the original work.
No Derivatives (ND): This symbol means you cannot change the work in any way. No derivatives allowed.
Non-Commercial (NC): This symbol means that you cannot use the work for commercial purposes. If you'd like to use the work for commercial purposes, you must ask the owner for permission.
Share Alike (SA): This symbol means that, if you share the work, you must do so under the same terms as the original license. For example, if I use a work that has a CC-BY-NC license, I might be able to make derivative works, but I must share my version under a CC-BY-NC license as well.
You can find CC-licensed materials, plug into the open access community, and choose CC licenses for your own works at https://creativecommons.org/.
The open education movement uses open and freely available educational materials, known as open educational resources (OERs) in order to alleviate the high cost of textbooks.
Open education resources operate on a 5R permissions framework that goes beyond being able to simply read items to:
This is often accomplished using Creative Commons licenses, which you might have seen on photos, videos, and articles available online.