Luck is when something good or bad happens to you by chance, not because of anything you did or didn't do. When you find a twenty-dollar bill on the sidewalk, that's good luck. When it starts pouring rain the moment you leave your umbrella at home, that's bad luck.

Luck is different from skill or preparation. If you study hard and ace a test, that's not luck: that's the result of your effort. But if the teacher happens to ask the one question you studied extra carefully, that's a bit of lucky timing. If you practice basketball every day and make a shot, that's skill. If the ball bounces off the rim three times before dropping in, that's luck helping you out.

People sometimes say someone is lucky when good things keep happening to them, or unlucky when bad things do. You might have a lucky pencil you like to use on tests, even though the pencil itself doesn't actually change anything. Athletes talk about the luck of the draw when they randomly get an easy or difficult opponent.

Some people believe you can make your own luck by working hard and being ready when opportunities appear. Others think luck is completely random.