The word slot is a noun and can refer to:
A slit or narrow opening, especially one that allows passage of a coin or other small object. A position or assignment. A slot in the track of a deer. A time or space reserved for an event, such as a flight or meeting. The allocation of slots to aircraft, allowing them to arrive and depart at the correct times, has led to enormous savings in delays and fuel burn. It is also an essential part of air traffic control.