1. The rights granted to a user to access, read, modify, insert, or delete certain data, or to execute certain programs. 2. Access privileges granted to a user, program, or process. 3.The granting of access to a security object. 4. The process by which an access control decision is made and enforced. 5. The granting of rights, which includes the granting of access based on access rights. 6. A mechanism that defines and controls what services or resources an entity can access.