in-joke
noun [ C ] uk/ˈɪn.dʒəʊk/ us/ˈɪn.dʒoʊk/
（只有圈子里的人才能懂的）内部笑话
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
英汉双解词典收录81607条英汉双解翻译词条，基本涵盖了全部常用单词的读音、翻译及用法，是英语学习的有利工具。