Dapper Day is like a big party where people dress up fancy and have fun. Imagine going to a big dress up party with your friends, but instead of dressing up like princesses or superheroes, everyone dresses up like they are going to a very fancy event.
Dapper Day started because some people really admired how folks used to dress up in the olden days, and they wanted to have some fun and celebrate dressing up like that. So they decided to pick a day and invite everyone to dress up all fancy like they did back in the olden days.
Now lots of people go to Dapper Day to dress up and have fun together. They might go to a fancy museum or go on rides at Disneyland. And since everyone dresses up so nicely, it feels like a really special occasion! It's a fun way to dress up and have some extra special fun with your family and friends.