Push notifications are automatic alerts sent from apps and web services to your smartphone. LINE messages, breaking news, and game events appear on your screen even when the app isn't open.
The name comes from the server "pushing" information to your device. The opposite is "pull," where you manually check for updates. Manually refreshing your inbox is pull; automatic new email alerts are push.
While convenient, too many notifications break concentration and drain battery. Toggle notifications per app in your phone's settings, keeping only essential ones. Use "Do Not Disturb" mode during class or sleep.
Phone-related push notifications include missed call alerts, voicemail notifications, and spam call warnings from blocker apps.