When you replay something, you play it again, whether it's a soccer match or a blues tune on your guitar. You can even replay, or repeat, a happy event over and over again in your mind.
If you take a video of your kitten playing with a ball of yarn, you can replay it any time you need a little cheering up. And in some sports, teams will replay a game that ends in a tie or is cancelled because of bad weather. This sports meaning is actually the oldest on record for replay, from an 1862 description of a curling match.