What term refers to a mature female rabbit?

The term that refers to a mature female rabbit is "Doe." In the context of animal terminology, "Doe" is widely recognized as the correct term for female rabbits, paralleling its use in other species such as deer. This term is used consistently among breeders and veterinarians to identify female rabbits of breeding age or older.

Looking at other choices, "Jill" refers to a female ferret, "Kit" is the term for a young rabbit, typically a baby rabbit, and "Buck" refers to a male rabbit. Thus, "Doe" is the appropriate and scientifically accepted term for a mature female rabbit, making it the right choice in this context.