A narrow opening or groove, especially in something like a piece of wood or a door. Also: The name of a slot in a computer motherboard, which holds expansion cards such as an ISA slot, PCI slot, or AGP slot. A thin opening in a door or window that allows for mail to be dropped through it. A place in a game of hockey where the center or winger has the best chance of scoring a goal without a deflection, because it gives them a straight-on view of the net. The area in front of the goaltender, between the face-off circles, is called the low slot; the area above the circles is the high slot.

In the old days, you pulled a lever and either won or lost. Today, computerized slots let players bet on up to 200 lines at a time — up, down, sideways and diagonally, each with a different chance of winning. A win occurs when all the symbols match on an active payline, which is shown in the game’s help screen before you start gambling.

Air traffic control also uses the term slot to refer to a scheduled time for an aircraft to take off or land, as authorized by the airport or air-traffic controller. For example, “We’ve got four landing slots for the new airline.” The word may also refer to an actual vacancy in an editorial position: “I’m afraid I can’t find anybody with enough experience to fill that slot at the Gazette.” The term is derived from electromechanical slot machines’ tilt switches, which made or broke a circuit and triggered a malfunction alarm.