Etiquette is the set of unwritten rules about polite behavior in different situations. It's knowing which fork to use at a fancy dinner, how to introduce two people who don't know each other, or when to say “excuse me” if you need to interrupt a conversation.

Every culture and setting has its own etiquette. In Japan, it's polite to slurp your noodles loudly to show you're enjoying them, while in America that would be considered rude. At a formal concert, good etiquette means staying quiet during the performance, but at a baseball game, cheering loudly is expected and encouraged.

Etiquette isn't the same as morality or law. Breaking etiquette won't get you arrested, but it might make others uncomfortable or think you're rude. Using proper etiquette shows respect for the people around you and helps social situations run smoothly. When you write a thank-you note after receiving a gift or hold the door for someone carrying packages, you're following etiquette.

Today, understanding etiquette helps you navigate everything from classroom discussions to job interviews to formal events. Different situations call for different etiquette: what works at your best friend's birthday party wouldn't work at a wedding or a museum.