Yeah, so the terminology used to label the folks who cross gender lines can be VERY confusing. Here's a quick list from straight to gay to give you an idea of what means what.

Asexual - Does not reproduce sexualy (animals...virgins XD)

Heterosexual - Attracted to the opposite sex

Crossdresser - A person, often male, who may wear clothing often assigned to the other gender usually for the sake of fetish, comfort or fashion. This can usually mean just one article of female clothing, or more (I.E just stockings, just pantyhose, just girl shoes, etc. Could be a combination of either) Does not necessarily mean gay. In fact, many straight married or female dating men like to wear womens clothing for how they feel or other "non-gay" reasons

Drag Queen - A male who dresses as a woman, often for competitions and recreation. Usually gay or bisexual, but not always. These people may spend a majority of their lifetime working on thier "queen" status, though they may maintain a "normal" working or other life as a male in "male" clothing  Drag Queen - A male who dresses as a woman, often for competitions and recreation. Usually gay or bisexual, but not always. These people may spend a majority of their lifetime working on thier "queen" status, though they may maintain a "normal" working or other life as a male in "male" clothin.

Drag King - Same as above, though with a woman that dresses as a man. Usually not that common and many if not most Drag Kings are serious about feeling "masculine"

Transvestite - A person, usually male, that wears women's clothing often for fetish or fun. More than often, Transvestites are either bisexual or gay, but not always the case. "TV's" usually go a little bit out their way to dress up like women other than just clothes, such as makeup, lipstick nails, wigs, shaving, perfume, and possible skin treatments (tanning, anal bleaching, lotions, etc).

Trap - Internet slang for a male that appears like a natural born female with little to medium effort. Usually a term for young boys that feminine features or less pronounced masculine features. A good example is "Linetrap" before she came known as Harley Quinn or Bailey Jay. Sexuality varies

Transgendered - Often confused with Transexual, though not always interchangable. If I remember correctly, it is a term for somebody (male or female) who doesn't feel like they are in the right gender. Usually the case when a male feels like he's a woman or a woman feels like she is a man, despite their chromosomes

Transexual - A term applied to any sex that has sucessfully transitioned from one sex or another. Some may keep their original genetalita after taking hormones, surgery or other treatments to appear as the opposite sex. 

Shemale/Ladyboy/Kathoey/TGirl/Newhalf - A term that varies per location to describe a male that has sucessfully transitioned from male to female(MTF). Shemale and Transexual are usually used in Spanish, Latin, Hispanic and English countries (with their respective translations). Ladyboy and Kathoey often refer to Thai Transexuals, though Ladyboy is commonly used for any Asian Transexuals. TGirl or "Gurl" is often short hand or slang for MTF transexuals, though has been used for transvestites as well. Newhalf is commonly used for Japanese MTFs. Transexuals are usually categorized by "pre-op" or "post-op". Pre-op means they have kept their penis while Post-op means they have had it removed.

Transfag - Slang/Insult used to describe a woman that has transitioned to a man. I haven't heard any other unique term used to describe them, though they may be more stingy about being prefer to be called a man and not a woman.

Bisexual - A person who is attracted to both male and female sexes.

Omnisexual/Pansexual - I don't really know the difference off the top of my head between the two, but these terms are often used to describe a person who can find sexual attraction regardless of sex. This may mean they are attracted to men, women, and "inbetweens", though they could easily favor one sex over another, though not always. These people often say "There is no gay or straight". I (pr0n_glutton) fall somewhere in this category....or maybe asexual >.>

Hermaphrodite/Intersexed - Somebody born with chromosomes from both sexes. They may appear male OR female and male have more pronounced male characteristics/Gentials OR female characteristics/Gentials.

Futanari/DickGirls - Term used to decribe animated female characters that have penises, often to those that have large penises with a visible vagina instead of testes (which are sometimes considered "inside"), though, they may or may not have balls sometimes. This is rarely but sometimes used as slang for Hermaphrodites or a trap/shemale that appears as a gentically born female

Homosexual -Used to describe some one that is only attracted to their own sex. "Gay" is often applied to men, though have been used for both sexes. "Lesbian" is exclusively for women. (lucky them)