A woman who is skilled in or adept at a wide variety of tasks or abilities (i.e., the female equivalent of "Jack of all trades"). If used with "master of none," it implies that while competent in a variety of things, she is not highly skilled in a particular one. I've had all sorts of different jobs through the years, so I consider myself quite a Jill of all trades! Mary just sort of floated between different interests after she left high school—a Jill of all trades, but master of none.