April fools' day | definition april fools' day , Define april fools' day: april 1 characteristically marked playing practical jokes. https://www.merriam-webster.com/dictionary/April%20Fools'%20Day April fools' day origins - snopes. | definitive, Claim: april fools’ day began 1500s gregorian calendar julian. forgot change attempted celebrate. https://www.snopes.com/holidays/aprilfools/origins.asp Top 10 april fools' day pranks | howstuffworks, The origin april fools' day . spike medford/­getty images ­ recorded april fools' day prank pulled 1627 madcap irishman named edmund 'neely.. https://people.howstuffworks.com/culture-traditions/holidays-other/top-10-april-fools-pranks.htm