slots 4

https://fair-wiki.win/index.php/Why_a_Smooth_Sign_Up_Process_Matters_for_Online_Gaming_Platforms

Slots are those little grooves or openings you see on a machine, a piece of furniture, or even in your schedule. Think of a vending machine where you drop a coin, or a wooden board with a channel for a drawer to slide into. In electronics, they're the bays where you plug in expansion cards. And if you're talking about a time slot, that's a reserved interval for a meeting or a TV show. It's all about a designated space or time for something specific to fit.