baker's dozen

"Baker's dozen" refers to a phrase or term used to describe a group of thirteen items, instead of the usual twelve. This term originated from bakeries in medieval England where bakers would give customers an extra loaf of bread for every dozen they purchased. This was done to avoid any potential penalties or accusations of shortchanging the customers, as the extra loaf acted as a guarantee. Therefore, a baker's dozen became a common phrase to denote a quantity of thirteen.