Trick’ is a synonym for the word ‘prank’ which means ‘to fool someone.’ The term ‘treat’ is something nice and delicious, like candies and chocolate. The phrase ‘trick or treat’ kids use on Halloween to say that if you don’t give them treats, they will perform a trick on you. Before saying this famous phrase, kids dress up in costumes and mainly in groups and go to different houses in the neighborhood. Then they knock on doors and say together ‘trick or treat!