The in-crowd is a small group of people who are “in” — popular, fashionable, or holding power — and who do not easily let others join. School, office, club, industry: there is often an in-crowd. From the outside the word has a little sting; it is rarely a kind name. People inside the group may not call themselves that. Though actually, magazines also use the in crowd in a lighter way, just meaning “the cool people right now,” without as much of the closed-door feeling. Younger speakers may prefer the popular kids or the inner circle, but everyone still understands in-crowd. It is not a formal word.