The queer community is growing rapidly but it's changing just as fast. New terms and new ideas are added all the time and it can be hard to keep up with everything. This is not a comprehensive list, but it's a good start to know these common terms.
Queer: An umbrella term to refer to people who are not straight and cisgender. This includes the entire LGBTQIA+ spectrum.
Sexual orientation: Refers to who a person is sexually attracted to, includes identities such as gay, straight, pan, etc.
Homosexual: A sexual orientation describing a person who is attracted, sexually, or romantically to people of their own gender.
Heterosexual: A sexual orientation describing a person who is attracted, sexually, or romantically to people of the opposite gender.
Gay: A sexual orientation describing a person who is attracted, sexually, or romantically to people of their own gender; commonly (but not exclusively) used to describe men.
Lesbian: A woman who is romantically or sexually attracted to other women.
Bisexual: A person who is romantically or sexually attracted to more than one sex or gender.
Pansexual: A person who can be attracted to all different kinds of people, without biological sex or gender being a factor.
Asexual: A person who experiences no sexual attraction to other people.
Demisexual: Someone who does not experience sexual attraction to anyone until they have a strong emotional connection.
Same-gender loving: A term some people in the African-American communities use instead of lesbian, gay, or bisexual to describe sexual attraction to people of the same gender.
Aromantic: A person who experiences little or no romantic attraction to others.
Gender identity: A person's concept of themselves as male, female, or neither. This may or may not be the same as the person's biological sex.
Gender role: The stereotypes and social behaviors assigned to by culture to each sex. (Ex: girls like dolls and boys like trucks)
Transgender: A person whose gender identity is different from the biological sex they were assigned at birth
Cisgender: A person whose gender identity is the same as the biological sex they were assigned at birth
Non-binary: A Person who doesn't identify exclusively as female or male.
Genderqueer: A person whose gender identity is often fluid, they may identify as male, female, both, neither, or a combination of male and female.
Agender: A person who doesn't identify as any gender.
Gender-expansive: An umbrella term used to refer to people who don't identify with traditional gender roles.
Gender fluid: A person who doesn't identify with a single gender, their gender identity may shift.
Gender non-conforming: A person who doesn't conform to traditional expectations or stereotypes of their gender.
Transsexual: A person whose gender identity does not align with the sex they were assigned at birth, and who takes medical steps such as sex reassignment surgery or hormone therapy to change their body to match their gender.
Transvestite: A person who dresses in clothing that is generally associated with the opposite gender or sex. Androgynous: A person who displays both masculine and feminine characteristics making it hard to tell their gender or someone that displays appears to be of one gender but displays characteristics generally associated with the opposite one.
Sexual and Romantic Orientations
Heteroromantic: romantic attraction to people of the same gender
Homoromantic: romantic attraction to people of the opposite gender
Biromantic: romantic attraction to people of multiple or any gender
Panromantic: romantic attraction to people without gender being a factor
Aromantic: lack of romantic attraction, although they may still experience sexual attraction
Sex-Favorable: Enjoys sex and is willing to compromise with a partner to find ways to receive and give pleasure.
Sex-Neutral (or indifferent): Neutral or indifferent toward sex, may be willing to compromise with a partner to give or receive pleasure but doesn’t find it intimate or fulfilling
Sex-Adverse: Does not enjoy sex and is generally unwilling to compromise with a partner.
Sex-Repulsed: Does not enjoy sex and is distressed at the thought of it, completely unwilling to compromise with a partner.
Coming out: The process of accepting one's sexual and gender identity and telling others about it, commonly family and friends.
Closeted: An LGBTQIA+ person who keeps their true gender or sexuality hidden from the world.
TERF: The acronym for "trans exclusionary radical feminists," referring to feminists who are transphobic.
Intersectionality: The concept of how a person's overlapping identities — including race, class, ethnicity, religion, sexual orientation and disability status — impact the way they experience oppression and discrimination.
As I stated before, this is not a comprehensive list but it is a good start when learning about this community or about yourself.