One of the first hurdles we parents face is the array of bewildering definitions. How is transgender defined? How does this differ from transsexual? What does FTM and MTF mean?
The following is a comprehensive list of definitions supplied by the website of Transgender Niagara.

Definitions from the website
  • Sex: The biological physical body, it reproductive organs, it's secondary sex characteristics. Male and female as it is defined by doctors at birth.
  • Gender: The social construct that masculinity and femininity are attributable to male and female physical bodies.
  • Gender Identity: A person’s intrinsic sense of self, regardless of the physical body's primary or secondary sex characteristics. The internal sense of manhood or womanhood.
  • Transgender: "Transgendered" is a term commonly used in one of two ways.
    • An umbrella term that serves as a banner to cover all those that transgress society's notions of how biological sex and gender link together. (anyone who crosses society gender norms). Many transsexuals disagree with using the word this way because it ignores the immense difficulties faced by transition and they do not feel that they cross society's gender norms by simply transitioning. We caution against using the word in this way.
    • A distinct category separate from transsexual that describes a person who feels society is limiting his or her personal expression by maintaining two distinct gender constructs, but is otherwise content with the sex category that was assigned at birth.
  • Transition: This is the period during which transsexual persons begin changing their appearance and bodies to match their internal identity. Because these changes are so visible, they must literally "out" themselves to everyone, such as co-workers, families and friends. While in transition, they are highly vulnerable to discrimination. While gays, lesbians and bisexual people may have some choice about outing themselves, transsexuals usually do not.
  • Transsexual Woman: This is a person whose designated sex at birth was "male", but has come to realize that she is a woman. She may be pre-hormonal, post-hormonal or non-hormonal as well as pre-operative, post-operative or non-operative. Regardless of what point she is with her transition, if she is identifying as female, she is to be considered female, and referred to with female pronouns. Always validate a person's chosen identity.
  • Transsexual Man: Likewise, a transsexual man is a person whose designated sex at birth was "female" and has realized he is actually a man. Regardless of what point he is with his transition, if he is identifying as male, he is to be considered male, and referred to with male pronouns. Always validate a person's chosen identity.
  • MTF/FTM: These terms originally were used only to describe transsexual people, but now are used to describe a larger spectrum of transgender and transsexual individuals and simply indicate the "direction" of cross-gender identification. Male-to-Female or Female-to Male.
  • Transphobia: This is the fear, hatred, disgust and discriminatory treatment of people whose real or perceived gender identity or gender presentation does not match, in a socially accepted way, the sex they were assigned at birth. Transgender people, transsexuals and intersexuals are typically the targets of transphobia.
  • Biocentrism: This is the assumption that people whose assigned sex at birth matches their gender identity throughout their lives are more "real"/and or more "normal" than are those whose assigned sex at birth is incongruent with their gender identity. For instance, women's shelters may be uncomfortable serving transsexual/transgendered women with the fear that their non-trans clients would be uncomfortable. Underlying this is a biocentric attitude that transsexual women aren't real women. When a service implies that trans women clients should be "grateful" when they are included in "women only spaces", this is also an example of biocentrism.
  • Intersexed: Formerly known as "hermaphrodite." The preferred term for persons born with what is insensitively referred to as "ambiguous" genitalia and/or chromosomal anomalies. Parents are often coerced by the "medical experts" to have their children's genitalia "normalized" often resulting in the loss of sexual response and/or assignment to the wrong gender.