It's right there in the back of my mind what the word is I'm looking for, but I'm not able to retrieve it. Here's the sentence, can you help me fill in the blank? Every doctoral student who received their degree from Judith, and others who knew Judith well, were conspirers in perpetuating a long-running ______ of calling Judith by her childhood name, “Eddie.” The word "joke" is not what I'm looking for. What I want is more about a deep sense of close familiarity only known to a few people. "Tradition" isn't right either.