What does BB mean from a girl to a girl?

Could you clarify what context you're referring to when you ask about "BB" from a girl to a girl? In general, abbreviations and acronyms can vary greatly in meaning depending on the context and community they're used in. "BB" could potentially stand for a variety of things, such as "baby," "best buddy," "be back," or even something more specific to a particular group or subculture. Without more context, it's difficult to say for sure what "BB" means in this particular situation. Is there any additional information you can provide to help narrow down the possible meanings?