April Fools' Day (sometimes called All Fools' Day) is celebrated every year on April 1 by playing practical jokes and spreading hoaxes. The jokes and their victims are called April fools. People playing April Fool jokes expose their prank by shouting April Fool. Some newspapers, magazines, and other published media report fake stories, which are usually explained the next day or below the news section in small letters. Although popular since the 19th century, the day is not a public holiday in any country.
In the UK, an April Fool joke is revealed by shouting "April fool!" at the recipient, who becomes the "April fool". A study in the 1950s, by folklorists Iona and Peter Opie, found that in the UK, and in countries whose traditions derived from the UK, the joking ceased at midday. A person playing a joke after midday is the "April fool" themselves.
In Scotland, April Fools' Day was traditionally called 'Huntigowk Day', although this name has fallen into disuse. The name is a corruption of 'Hunt the Gowk', "gowk" being Scots for a cuckoo or a foolish person; alternative terms in Gaelic would be Là na Gocaireachd 'gowking day' or Là Ruith na Cuthaige 'the day of running the cuckoo'. The traditional prank is to ask someone to deliver a sealed message that supposedly requests help of some sort. In fact, the message reads "Dinna laugh, dinna smile. Hunt the gowk another mile." The recipient, upon reading it, will explain he can only help if he first contacts another person, and sends the victim to this next person with an identical message, with the same result.
In England a "fool" is known by different names around the country, including a "noodle", "gob", "gobby" or "noddy".
In Ireland it was traditional to entrust the victim with an "important letter" to be given to a named person. That person would then ask the victim to take it to someone else, and so on. The letter when finally opened contained the words "send the fool further".