April fool แปลว่า

"APRIL FOOL, Any one imposed on, or sent on a bootless errand on the first of April, on which day it is the custom among the lower people, children, and servants, by dropping empty papers carefully doubled up, sending persons on absurd messages, and such like contrivances, to impose on every one they can, and then to salute them with the title of April-fool."

"The best April fool ever perpetrated was 1 April 1698 and made a laughing stock of the gentry of London, great numbers of whom turned up in their carriages and finery at the Tower of London to 'see the lions being washed' as instructed on their gilt-edged invitation cards."