allow(To permit someone else to perform an action. For example, to let someone else see your online status, send you messages, or see your public Messenger information)
permissions(Authorization to perform operations associated with a specific shared resource, such as a file, directory, or printer. Permissions must be granted by the system administrator to individual user accounts or administrative groups)
Allow(A permission setting that permits a person or domain to add the user to contact lists, see the user's status, or send instant messages to the user)