Payline is a casino term used to describe a feature of slot machines in brick-and-mortar casinos and video slots in online casinos.
In order to win while playing slots, you need to land a winning combination on a payline. Since you get paid for doing so, you can see why those lines are called paylines.
Depending on the slot’s design, a game can have as little as three paylines or as much as several hundred thousand paylines. They usually come in horizontal or zigzag patterns that go across the reels, but if there are hundreds of them in a video slot, they can often have irregular patterns.
Before you start playing a video slot, you can access its paytable where you can see how many paylines a video slot has, as well as their patterns.
Another thing to note is that video slots can either have a fixed or adjustable number of paylines. If the paylines are adjustable, players can select the number of paylines they wish to play with or choose paylines that increase in number during bonus features.