In computer security, a permission is quite different from a privilege. A permission is a property of an object, such as a file. It says which agents are permitted to use the object, and what they are permitted to do (read it, modify it, etc.). A privilege is a property of an agent, such as a user. It lets the agent do things that are not ordinarily allowed. For example, there are privileges which allow an agent to access an object that it does not have permission to access, and privileges which allow an agent to perform maintenance functions such as restart the computer. https://english.stackexchange.com/a/46305