Push notification
A push notification is a form of communication that is sent to a device, most commonly from software developers providing information or updates to their applications. Since the information is sent to the user's device (in other words, the information is pushed to the user), the user does not need to open the application or perform any action to receive the notification (which would instead be pulling the information).
Push notifications are very common with cellular phone applications and can be used with certain smart phones such as iPhones and Android phones.
Also see: Cell phone definitions