"FNDM" stands for "Fandom," which refers to a community of passionate fans who share a common interest in a particular subject, such as books, movies, TV shows, or games. The combination of the symbols "🔍🧩📚" could represent the curiosity and puzzle-solving nature of fans within a fandom, as they delve deep into the details, analyze, and explore various aspects of their favorite content, like detectives piecing together clues from a book.