The most commonly used Trans flag
Transgender (usually shortened to trans) is a gender where someone does not identify with their assigned sex at birth, It commonly refers to men who were assigned female at birth (trans men), and women who were assigned male at birth (trans women) these two examples are known as binary trans people. All non binary people are also classified as transgender as included by the white stripe, however they may not and do not have to identify with the term transgender, and can use another term for whatever they feel fits them best.
There are other terms that exist, such as non-binary, agender, gendernull, genderfluid, or genderflux, but they do not have to use those terms either.
History[]
The Transsexual flag
The term transgender has a lot of history behind it. Transgender used to be called "transsexual" alongside the term transgender. Transsexual was a more medical and psychological term. The term is still used by some older transgender individuals and transgender individuals comfortable with the label. Transsexual can also be used by trans individuals who would like to change their body through surgeries, but transgender is the preferred term because it is less medical.