(1) In computer security, the right granted to a user to communicate with or make use of a computer system.
(2) The process of granting a user, system, or process either complete or restricted access to an object, resource, or function.
(3) The process by which data in the database catalog is used to obtain information about an authenticated user, such as which database operations the user can perform and which data objects the user can access. See also privilege, authority level, database authority.
(4) The process of granting or denying access to a network resource. Security systems use a two-step process: after authentication has verified that a user is who she says she is, authorization allows the user access to various resources based on the user's identity.
(5) The method that determines which portlets a user or a user group can access.
(6) The process of obtaining permission to perform specific actions.