Butch is a general term that covers a wide spectrum of masculine identified women. A lot of butch women will tell you that they always felt and acted masculine, even as a child, but some don’t express that part of themselves until later in life.
Butch women are what comes to mind when most people hear the word dyke. They don’t have to come out because most people can just tell. Ivan E. Coyote commented that her closet “has always been made out of glass.”
Some butch women try to fill the stereotypical male gender role entirely, others pick and choose.
A lot of butch women are primarily interested in femmes, but some prefer other butches.