a traditional jester's cap or hood, often multicolored and usually having several drooping peaks from which bells are hung.
Origin of fool's cap
First recorded in 1625–35
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
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