A slot is a narrow opening in a machine or container, for example a hole that you put coins in to make a machine work. He dropped a coin into the slot and dialled the number. If you slot something into something else, or if it slots into it, you put it into a space where it fits. He was slotting a CD into a CD player.

A slot attendant works in a casino, monitoring the slot machines. Your duties are to report machine glitches, distribute winnings when necessary, and handle complaints from unhappy players. Additionally, you are responsible for surveillance of your section.