Many OERs are licensed through Creative Commons. Creative Commons (CC) licenses are explicit statements of how you allow others to use your work. This licensing makes it easier for others to know your intentions and facilitate the reuse of anything you plan to share.
The Creative Commons system uses symbols, in part, to denote different types of Creative Commons licenses. Here is a list of the most commonly used CC symbols which correspond to the license types listed below.
CC – Creative Commons.
BY – Attribution
NC – Noncommercial uses
ND – No derivative uses
SA – Share alike
This is the most permissive of CC licenses offered. CC BY allows others to distribute, remix, tweak, and build upon your work, even commercially, as long as they credit you for the original creation.
This license lets others remix, tweak, and build upon your work even for commercial purposes, as long as they credit you and license their new creations under identical terms.
This allows others to redistribute your work—commercially or non-commercially—as long as they credit you and do not alter your work.
This lets others remix, tweak, and build upon your work for non-commercial purposes as long as they acknowledge you.
This license lets others remix, tweak, and build upon your work non-commercially, as long as they credit you and license their new creations under identical terms.
This license is the most restrictive, allowing others to download your works and share them with others as long as they credit you. But they may not change your works or use them commercially.
This symbol means that the item is free of known copyright restrictions. It is used for very old works whose copyright has expired.