0 a private joke that can only be understood by a limited group of people who have a special knowledge of something that is referred to in the joke -- （只有圈子里的人才能懂的）内部笑话
Allegedly he was very serious in the bar and this led to an in-joke whereby all his companions ascribed all new jokes to him.
Other times a fictional corporation is an in-joke carried across multiple products by the same games developer, director, or writer.
Mathematical jokes are a form of in-joke, generally designed to be understandable only by insiders.
If you loathe character development, intelligent satire, and in-joke movie references, do not watch this flick.
The catalog number is an in-joke reference to her birthday and initials of her name.
The line had developed as something of an in-joke.
It has become something of an in-joke to buy the school clocks for classrooms.
This had become a bit of an in-joke amongst those behind the podcast.
