On TikTok, the acronym "BSF" primarily means "best friend," similar to terms like "bestie" or "bff" (best friend forever)
. It can also sometimes mean "best sister friend," referring to a friend who is as close as a sibling but not actually related
. The abbreviation "BSF" is used to differentiate from "BF," which commonly stands for "boyfriend"
. In summary, on TikTok, "BSF" is a popular slang term for a very close friend, often interchangeable with "best friend" or "bestie"
