Why do they call it naptime when nobody naps

Every single day at 2pm I try to convince my kids that naptime is 'nap time' not 'destroy the house while being weird time' but apparently I'm fluent in a language nobody else speaks. Today my 5 year old had a 20 minute meltdown because his PB&J was cut into triangles instead of rectangles. TRIANGLES. His exact words were 'this is unacceptable, father.' Where do they get this stuff?