The slot is an area of a machine that can be used to store different types of objects. Unlike a cache, which holds frequently changing files, the slot is more permanent. The slots are often arranged in groups to maximize storage capacity.

A slot is a narrow aperture or groove, usually vertical, for receiving something such as a coin or a label. It may also refer to a position in a sequence or series, an appointment or job opening, a berth or seat in an aircraft or ship, or a place to stop or rest. The word is derived from the Old English noun slot, meaning “a narrow opening, hole, or gap.”

Until recently, a player dropped coins into slots to activate the games for each spin. However, this changed with the introduction of bill validators and credit meters that allow players to play for credits rather than cash. These devices have allowed many gamblers to view their gambling as a hobby and not just a business.

While Hirsch is an important figure in the history of casino slots, it was William Redd who led their transformation from a marginalized afterthought to the largest source of casino revenue today. His innovation spanned the entire industry and eliminated many of the weaknesses that Hirsch and others had dismissed as insignificant. He also developed a series of milestones that helped to modernize the form and function of slots, eliminating many of the shortcomings that had made people like Hirsch dismiss them with derision.