Authorization is official permission to do something. When you get authorization, someone in charge has said “yes, you can do that.” A library card gives you authorization to check out books. A hall pass is your authorization to be out of the classroom during school hours. Without that signed pass, you're not authorized to be in the hallway.

The word comes from authority, meaning power or the right to make decisions. When someone has authority over something, they can grant authorization to others. Your principal has the authority to authorize a field trip. A doctor's note authorizes you to miss gym class. A parent's signature authorizes a permission slip.

Authorization often comes in written form: signatures, passwords, tickets, badges, or official documents. These prove you have permission. When you log into a computer account, the system checks whether you're authorized to access it. A security guard might ask to see your authorization before letting you into a restricted area.

Authorization means you have legitimate permission, the official right to act. You might be physically able to take a book from the library without checking it out, but you're not authorized to do so because you don't have that official permission.