April FOOLS' Day is an annual celebration on April 1st, where people play practical jokes and hoaxes on each other. It is believed to have originated in the 1500s in France, when people began celebrating the start of the new year on April 1st instead of January 1st. The term 'April FOOLS' Day' is thought to have come from the French phrase 'Poisson d'Avril, ' which translates to 'April Fish.' This is because a young fish is easily fooled by bait.