a traditional jester's cap or hood, often multicolored and usually having several drooping peaks from which bells are hung.
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Origin of fool's cap
First recorded in 1625–35
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
British Dictionary definitions for fool's cap
a hood or cap with bells or tassels, worn by court jesters
a dunce's cap
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012