When you sneeze, air explodes out of your nose and mouth suddenly and forcefully, usually because something has irritated the inside of your nose. Your body does this automatically: you can't really control it once it starts. That tickly feeling in your nose, the quick intake of breath, and then achoo! That's a sneeze.

Sneezing helps protect you by blasting out dust, pollen, or germs that shouldn't be in your nose. Some people sneeze when they look at bright lights (called a photic sneeze reflex), and many people sneeze multiple times in a row. When you feel a sneeze coming, it's polite to cover your nose and mouth with a tissue or your elbow, not your hands, since sneezes spray tiny droplets that can travel surprisingly far and fast.

The word can also mean to treat something as unimportant. If someone says a problem is nothing to sneeze at, they mean it actually is serious and shouldn't be dismissed. A prize of $500 might not sound like much to an adult, but it's definitely nothing to sneeze at for a kid saving up for something special.