I am always confused between difference and different, although I knew difference is a noun and different is an adjective, but still I might use it wrongly.

For an example, we are suppose to say today you drove a different car, not difference car, but when I ask about the car, I say what is the difference in your car? and not different. Then I say different sex and difference in sex, different sex means the other gender, but difference in sex means differences in sexuality.

So my lecturer asked yesterday, what is the difference between transsexual and transvestite? Well, transsexual is the person who change their original sex by undergoing an operation to change their sexual organs, but transvestite is a person who like to wear different gender clothes, just like a boy wearing a woman's dress.

Anyhow, my lecturer only related transsexual to a boy changing into a girl, what about a girl who cut off their breasts and want to be a boy?