A position within a group, series, sequence, or organization; also, the time and place authorized for an aircraft to take off or land, as assigned by an airport or air-traffic control. Originally, the term was applied to a gap in the wing or tail surface of an airplane used in connection with a high-lift or control device; the meaning expanded to include any of a number of other openings in the aerodynamic surfaces of an aircraft, especially those employed for purposes of flight stability and maneuverability. From 1940, the sense has broadened to mean any open position in a group or sequence; hence, the idiom, to be “in the slot.”

In slot machine play, a line on which payouts may be earned based on winning combinations of symbols. Slots usually have a number of pay lines and vary in theme from classic objects such as bells and stylized lucky sevens to more exotic creatures or locations. Depending on the game, players can insert cash or, in the case of ticket-in/ticket-out machines, paper tickets with barcodes into the machine. Afterward, they activate the machines by pressing a lever or button (either physical or virtual on a touchscreen), and the reels spin and stop to rearrange symbols.

The odds of a particular symbol appearing on a payline are proportional to its frequency on the physical reel, but due to the complexity and fast pace of electronic games, it is impossible to display the odds directly on the machine. As a result, many players assume that some machines have a better chance of paying out than others. This belief is not only incorrect, but can be damaging to a player’s bankroll if they become greedy and bet more than they can afford to lose.