Permission is a license to do something, in some cases authorizing a person or entity to do an act which without such authority would have been unlawful (or subject to possible liability). Permissions may be sought for a wide range of actions. For example, permission may be required in the release of confidential information to a third party, such as medical records, or for the use of copyrighted material.
Permissions are often used in school settings. Schools often require parental permission for students to attend field trips or participate in extracurricular activities.