in-joke
US /ˈɪn.dʒoʊk/
UK /ˈɪn.dʒoʊk/

1.
piada interna, piada particular
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.
A conversa deles estava cheia de piadas internas que eu não entendia.
•
You had to be there to get the in-joke.
Você tinha que estar lá para entender a piada interna.