in-joke
US /ˈɪn.dʒoʊk/
UK /ˈɪn.dʒoʊk/

1.
内部笑话, 圈内笑话
a joke that is understood only by a small group of people who are familiar with a particular subject or situation
:
•
Their conversation was full of in-jokes that I didn't understand.
他们的谈话充满了我不懂的内部笑话。
•
You had to be there to get the in-joke.
你必须在场才能理解这个内部笑话。