To smile means to turn up the corners of your mouth to show happiness, friendliness, or amusement. When you smile, your face lights up, and people can tell you're feeling good or trying to make them feel welcome.

Smiling is one of the first expressions babies learn, and it's something people do in every culture around the world. You might smile when you see an old friend, when you hear a funny joke, or when you're proud of something you've accomplished. Sometimes people smile to encourage others or to show kindness, like smiling at a nervous new student to help them feel at home.

Scientists have discovered something interesting: smiling can actually make you feel happier, not just show that you're happy. The physical act of smiling sends signals to your brain that can lift your mood. And smiling is contagious. When you smile at someone, they'll almost always smile back without even thinking about it.

People can smile in different ways. A warm, genuine smile reaches your eyes and makes them crinkle slightly at the corners. A tight or forced smile might mean someone is trying to be polite but isn't truly happy. You've probably noticed the difference yourself when you see someone smile.