| Colloquial term for an extremely butch lesbian. Generally blue-collar (as it's awfully hard to break class barriers or even get a job when your identity is one that threatens the status quo), they have all the hardships of a socially denigrated role as well as an economic disadvantage. Bulldagger is related to/interchangable with bulldyke, and may evoke factory work, barfights, leather jackets, strength, confidence, worn jeans, alcoholism, depression, misunderstanding, isolation.
Bulldykes exist within the structure of butch/femme identities that was very common among lesbians in the 1950s, 60s, and 70s, and still exists today. Their acceptance of stereotypical masculinity (thus in some ways reinforcing a dichotic gender paradigm while at the same time challenging it) makes their identity a difficult-to-negotiate one, both in in theory and in praxis.
This term, like many, including the word dyke itself, can be used with respect and within the queer context, or with venom from without. See coopting derisive terms for a discussion of this phenomenon.
For an excellent book on living as and with bulldagger and other butch/femme identified lesbians, read Stone Butch Blues by Leslie Feinberg. (Stone butch is another term s/he uses for an extremely masculine, hard-edged butch. In the book s/he emphasizes the psychological hardening and shutting off that these women have to go through in order to merely survive. "Stone" butches are to be both respected and sympathized with.)
For what could well be an elaborate pseudoetymology, try http://www.ppct.org/tackling62.htm. It's kinda funny, in a reclaiming-and-reinterpreting-history kinda way. | 
