A payline refers to a line that can be either straight or zig-zagged, which intersects one symbol on every reel of a slot machine. It represents the specific combination of symbols on the reels that a player will receive a payout for if they have placed a bet on that particular combination. In order to qualify as a winning combination, there must be a minimum of two identical symbols in a consecutive row, with the first symbol appearing on the first reel unless specified otherwise. If these conditions are not met, the combination will not result in a payout.