Transgender does not have one definition. Instead it is a group of "identities and experiences of sex and gender variance, changing, and blending." This is when an individual's biological sex does not match up with which gender they identify themselves with. Under the umbrella of transgender includes "transsexual people, cross-dressers, drag kings and queens, genderqueer people, gay men and lesbians who queer gender lines, the partners of trans people, and any number of other people who transgress binary sex." These individuals often undergo sex-reassignment surgery, take hormones, or change their style of life to feel more comfortable.
Read more about this topic: Sex And Gender Distinction