What is a baker's dozen?

A baker's dozen typically refers to 13 items. Throughout history bakers made a practice of adding an additional 13th item to orders of a dozen items.

The actual reason for the 13th item in a baker's dozen is disputed. The most popular and supported theory is that many cultures carried extreme penalties for short changing an order, so bakers added an additional item to orders to ensure they exceeded the value a customer was expecting to avoid severe penalties. A second theory from the 1590s refers to the practice of adding a free 13th item to orders of 12 when selling to middlemen or wholesalers. The middlemen could then sell all 13 items at full price and realize a profit.