Because the word "transgender" is used to cover a wide variety of people, it is called an "umbrella" word. Many different types of people think of themselves as "transgender". Many different types of people are called "transgender". Different English speakers define words in different ways. For these reasons, the term "trans people" is often used.

Some common definitions of the words used in this article are listed here. These are common ways but not agreed to by everyone:

* Sex means whether someone was born with a male or female body.
* Gender means whether a role or way someone acts is masculine or feminine, though it can also mean neither masculine nor feminine.
* Gender identity is a person's sense in their mind of whether they are a man or a woman or something else.
* Binary or "Gender Binary" is the common idea that there are only two groups that a person can belong in: male or female. The "Gender Binary" idea also means that thoughts and actions are also "male or female". At the simplest level, this means that if a male child wants a doll, he is "acting like a girl". If a female child climbs a tree, she is called a "Tomboy". Nowadays, in many societies it is considered wrong to force children into traditional gender roles.

These definitions are important to help understand that what people look like outside (sex) is not always the same as how they feel inside (gender.) Some people do not fit well into the gender binary idea. People who are transgender usually want to be called by the pronoun (ze, he or she among others) that matches their gender identity, so this article will do that.

Who is transgender?

There are many groups who are included under the 'umbrella' of transgender. Some of the bigger groups are:
The artist Marcel Duchamp photographed by the artist Man Ray

* Transsexual – Someone who was born one sex and who has a different gender identity. Transsexual often means those people who take medicines and/or have surgery to change their body to fit their gender identity. For example a person born with a male body who feels inside that she is a woman and has surgery and takes medicines to make her body more female. Some transsexual people do not like this word and just call themselves transgender.
* Transgenderist – Someone who was born one sex but has a different gender identity. However, transgenderists often choose not to take medicines or surgery to change their bodies. Some, however, may try to make small changes to their bodies. They do often live in the other gender role, however (known as crossliving). For example, a person born with a female body who feels that he is a man inside, may act and dress like a man, may choose a job that men usually choose, may be treated as a man by his family and friends.
* Cross-dresser – This is someone who is born one sex but likes to sometimes wear the clothes and act like the other sex. However, this person may not feel like he is the other sex inside.
* Transvestite – This is a kind of cross-dresser who usually likes to cross-dress for sexual excitement. However, this word is used by some people in a negative manner. Some people use it to mean that cross-dressing for sexual pleasure is bad or abnormal.
* Genderqueer – This means someone who uses both male and female roles, look, or actions at the same time. It is not just a person who does not fit in the gender binary. Some genderqueer people reject the whole idea of a gender binary.
* FTM (acronym)– This means 'female-to-male.' It is someone who was born in a female body but who in some way feels or acts male. An FTM person is also sometimes called a transgender man, a transsexual man, or a transman.
* MTF – This means 'male-to-female.' It is someone who was born in a male body but who in some way feels or acts female. An MTF person is also sometimes called a transgender woman, a transsexual woman, or a transwoman.
* Intersex - is a medical word for people who are born with both some male and some female biological traits.