A slot is a narrow opening in something that allows for something to fit inside. For example, a slot in a machine that takes coins or paper tickets with barcodes is where you put the money or ticket in to make the machine work. You can also refer to a time slot in a schedule or program as a time when an activity can take place.
In computing, a slot is an area of the motherboard into which a processor can be inserted. This is designed to facilitate upgrading or adding capabilities to a computer, as opposed to replacing the whole motherboard. The term slot is also used to refer to a connection in a printed circuit board, such as an expansion card, that can be inserted into the mainboard of a computer. This is not to be confused with a bay, which is another site in the mainboard into which a disk drive can be installed.
In American football, a slot receiver (also known as a “slotback”) is a wide receiver who lines up close to the offensive line, but slightly behind the line of scrimmage. This position is often utilized to block defenders from sacking the quarterback, and it can also be used to catch passes from the tight end or running back. The slot receiver is most commonly used in three-reel formations, but is also a factor in four- and five-reel formations as well.