Silent mode disables all ringtones, notification sounds, and vibration for complete device silence. While manner mode notifies via vibration, silent mode suppresses everything including vibration. Used in cinemas, theaters, and exam halls where even vibration is unacceptable.
iPhone offers "Focus" modes including "Do Not Disturb" as its silent mode, with granular control over which contacts and apps can notify. Android provides "Silent Mode" or "Bedtime Mode" with scheduled auto-switching.
A critical exception: Area Mail emergency alerts force sound even in silent mode. However, airplane mode stops all radio communication, preventing emergency alert reception.
Using silent mode while sleeping risks missing urgent calls. iPhone's "Do Not Disturb" has "Allow Repeated Calls" - if the same person calls twice within 3 minutes, the second call rings through. Recommended for not missing family emergencies. See phone etiquette basics for more.