To snore means to make loud breathing sounds while sleeping. When someone snores, the soft tissues in their throat vibrate as air passes through, creating anything from a gentle rumble to a thunderous rattling that can wake everyone in the house.

Almost everyone snores occasionally, especially when they have a stuffy nose from a cold or allergies. Some people snore every night. The sound happens because when you're deeply asleep, the muscles in your throat relax, narrowing the airway and causing vibrations.

Snoring has been the subject of countless jokes and complaints. Someone might say their dad snores like a freight train, meaning his snoring is incredibly loud. On camping trips or sleepovers, one person's snoring can keep everyone else awake. In cartoons, sleeping characters often snore with exaggerated “ZZZZZ” sound effects (which explains why we sometimes draw the letter Z to represent sleep).

While snoring is usually just annoying, very loud or constant snoring can sometimes signal a health problem worth checking with a doctor. For most people, though, it's simply an embarrassing nighttime habit they can't control because they're sound asleep when it happens.