These terms are taken from Trans Student Educational Resources organization website:
Cisgender/Cis - Term for someone who exclusively identifies as their sex assigned at birth. The term cisgender is not indicative of gender expression, sexual orientation, hormonal makeup, physical anatomy, or how one is perceived in daily life.
Adjective that means “identifies as their sex assigned at birth” derived from the Latin word meaning “on the same side.” A cisgender/cis person is not transgender. “Cisgender” does not indicate biology, gender expression, or sexuality/sexual orientation. In discussions regarding trans issues, one would differentiate between women who are trans and women who aren’t by saying trans women and cis women. Cis is not a “mad up” word or slur. Note that cisgender does not have an “ed” at the end.
Transgender/Trans - Encompassing term of many gender identities of those who do not identify or exclusively identify with their sex assigned at birth. The term transgender is not indicative of gender expression, sexual orientation, hormonal makeup, physical anatomy, or how one is perceived in daily life. Also see: The Gender Unicorn.
An umbrella term for people whose gender identity differs from the sex they were assigned at birth. The term transgender is not indicative of gender expression, sexual orientation, hormonal makeup, physical anatomy, or how one is perceived in daily life. Note that transgender does not have an “ed” at the end.
Queer - A term for people of marginalized gender identities and sexual orientations who are not cisgender and/or heterosexual. This term has a complicated history as a reclaimed slur.
Gender Expression/Presentation - The physical manifestation of one’s gender identity through clothing, hairstyle, voice, body shape, etc. (typically referred to as masculine or feminine). Many transgender people seek to make their gender expression (how they look) match their gender identity (who they are), rather than their sex assigned at birth. Someone with a gender nonconforming gender expression may or may not be transgender.
Gender Identity - One’s internal sense of being male, female, neither of these, both, or other gender(s). Everyone has a gender identity, including you. For transgender people, their sex assigned at birth and their gender identity are not necessarily the same.
Sex Assigned at Birth - The assignment and classification of people as male, female, intersex, or another sex assigned at birth often based on physical anatomy at birth and/or karyotyping.
Sexual Orientation - A person’s physical, romantic, emotional, aesthetic, and/or other form of attraction to others. In Western cultures, gender identity and sexual orientation are not the same. Trans people can be straight, bisexual, lesbian, gay, asexual, pansexual, queer, etc. just like anyone else. For example, a trans woman who is exclusively attracted to other women would often identify as lesbian.
Transition - A person’s process of developing and assuming a gender expression to match their gender identity. Transition can include: coming out to one’s family, friends, and/or co-workers; changing one’s name and/or sex on legal documents; hormone therapy; and possibly (though not always) some form of surgery. It’s best not to assume how one transitions as it is different for everyone.
Transsexual - A deprecated term that is often considered pejorative similar to transgender in that it indicates a difference between one’s gender identity and sex assigned at birth. Transsexual often – though not always – implicates hormonal/surgical transition from one binary gender (male or female) to the other. Unlike transgender/trans, transsexual is not an umbrella term, as many transgender people do not identify as transsexual. When speaking/writing about trans people, please avoid the word transsexual unless asked to use it by a transsexual person.