This list is not intended to be comprehensive; it simply serves as explanation for the terms used in other pages on this site. It defines the way that I use these terms, not necessarily the way that other folk use them: the terminology associated with transgender issues is complex!
Transgender: a transgender individual identifies in some way as being a different gender from their biological gender. This may mean that they experience a sense of dissatisfaction with their birth gender, also known as gender dysphoria. This dysphoria may be relieved by occasionally presenting as the opposite sex (as in my own case), by living full-time in the other gender, or by having sex reassignment surgery (SRS) to permanently modify their physiological presentation.
Transvestite: somebody who dresses in the clothing of the opposite gender. A related term is “fetishistic transvestitism”, which describes an individual who experiences sexual arousal through dressing in the clothes of the opposite gender. Of late I have detected a blurring of the two terms, and prefer to refer to myself as “transgender” rather than as a “transvestite”.
Tranny: an abbreviation of “transvestite” that is now widely regarded as derogatory and offensive. I must say that I cheerfully referred to myself as “a tranny” for a number of years, using the term with a certain amount of irony. However, I have become increasingly sensitised to the negative connotations – in particular the assumption that to be trans is almost to be some sort of a prostitute – that I now no longer use it.
T-girl: a term widely used by transgendered folk to refer to trans-women. I’m now sufficiently old that referring to me as a “girl” would seem entirely inappropriate even if I had been born biologically female, so I tend not to like the term; in the same way that I don’t refer to grown women as “girls” I tend not to refer to transwomen as “t-girls”.
Transsexual: somebody who has “transitioned” to live full-time in the opposite gender. The question of whether or not the individual has had surgery seems to be less important to me than the fact that they have permanently adopted the cross-gender role.