A narrow notch, groove or opening, as in the keyway of a machine part, a slit for a coin in a vending machine, etc.

A position in a group, series or sequence; also, a time allotment for an appointment or other activity.

When you go to the casino, look closely at the carpeting, the tables, the chairs — everything has been carefully engineered to make gambling more seductive and get you spending more money. But almost nothing in a modern-day casino is more carefully engineered than the slot machines. And they are perhaps the most dangerous of all. As a new book by the journalist Annie Schull reveals, casinos have developed an arsenal of strategies to make their video gambling machines as addictive as possible. In her research, Schull visited casinos across the country and watched people play the slots. She found that for many, the slots have become less about the chance of winning big and more about the gradual drip feed of small wins that keeps them in the game.