Language is always changing. It's ok if you don't know what something means! There are so many ways to find out. Take the time to educate yourself, but don't get too hung up on finding the "correct" term - what matters most is understanding and respecting the language that people use to refer to themselves.
Here are a few terms used within the LGBTQIA+ community and some of their common definitions:
Ace: an abbreviated term for ‘asexual’.
AFAB: an abbreviated term for 'assigned female at birth.'
Agender: a person with no (or very little) identification with cultural understandings of gender and/or someone who sees themselves as existing without gender.
AMAB: an abbreviated term for 'assigned male at birth.'
Androgyny: a gender expression that incorporates elements of both masculinity and femininity and/or goes beyond that binary.
Aro: an abbreviated term for ‘aromantic’.
Aromantic: someone who does not experience romantic attraction.
Asexual: someone who does not experience sexual attraction.
Bigender: a person who identifies with a combination of two genders.
Binding: the practice of tightly wrapping one's chest to minimize the appearance of having breasts.
Bisexual: a person who experiences attraction to both people of their own gender and people of other genders. Sometimes used interchangeably with 'pansexual.'
Bottom surgery: gender affirming surgery that involves the alteration of external genitalia.
Cisgender: describes a person whose sex assigned at birth aligns with their gender identity in a culturally-normative way (i.e. male and masculine).
Demi-(a)sexual: someone who only experiences sexual attraction after establishing a close emotional and/or romantic connection.
Demi(a)romantic: someone who only experiences romantic attraction after establishing a strong emotional connection.
Drag: a theatrical performance of gender. Performers are often called 'Drag Kings' or 'Drag Queens.'
Feminine-of-center (FoC); masculine-of-center (MoC): a person who understands themselves as generally more feminine or masculine, but doesn't necessarily identify as a woman or man.
FTM: an abbreviated term for 'female-to-male;' usually a person who was assigned female and identifies as a man.
Gay: 1) experiencing attraction solely (or primarily) to people of the same gender. 2) historically used for people who identify as men who are attracted to other men. 3) an umbrella term used to refer to the LGBQ community as a whole.
Gender affirming surgery: Surgeries used to modify one’s body to be more congruent with one’s gender identity.
(Gender) dysphoria: mental or emotional dissonance between a person's internal experience of their gender and their physical body or sex assigned at birth. Can cause severe psychological distress.
Gender-expansive: an umbrella term for the wide range of gender identities beyond cisgender.
Gender expression: the way a person performs or shares their gender with the world through clothing, behavior, speech patterns etc. Gender expression does not necessarily align with gender identity in ways that are culturally expected (i.e. a person who wears dresses does not necessarily identify as a woman).
Genderfluid: a person who's experience of gender changes over time or does not fit within a fixed category.
Genderqueer: 1) a gender identity label used by people who do not identify with the binary of man/woman. 2) an umbrella term for a range of gender non-conforming or non-binary identities (e.g., agender, bigender, genderfluid).
Gender identity: a person's internal experience of their own gender.
Grey-(a)romantic: someone who sometimes, occasionally, or rarely experiences romantic attraction.
Grey-(a)sexual: someone who sometimes, occasionally, or rarely experiences sexual attraction.
Heterosexual: a person who solely (or primarily) experiences attraction to people of the 'opposite' sex assigned at birth and gender identity than their own. Often used interchangeably with 'straight'.
Homosexual: a person who solely (or primarily) experiences attraction to people of the same sex assigned at birth
Intersex: an umbrella term for people whose sex characteristics at birth do not align with the male-female binary; includes a wide range of natural variation in genetics, hormonal production, reproductive organs, and external genitalia.
Lesbian: a person who identifies as a woman who is solely (or primarily) attracted to other women.
LGBTQIA+: an abbreviated term for 'lesbian, gay, bisexual, trans, queer, intersex, asexual, and other identities.'
MTF: an abbreviated term for 'male-to-female;' usually a person who was assigned male at birth and now identifies as a woman.
Non-binary: a person whose experience of gender cannot be solely defined by either male/masculine/man or female/feminine/woman.
Sex assigned at birth: a person's sex as determined by the medical and cultural system in which they were born; often binary (male-female) or intersex and linked to external genitalia.
Straight: describes a person who solely (or primarily) experiences attraction to people of the 'opposite' sex assigned at birth and gender identity than their own. Often used interchangeably with 'heterosexual.'
Top surgery: gender-affirming surgery on the chest, often involving the removal or implantation of breasts.
Trans(gender): describes people whose gender identities do not match up with their sex assigned at birth. Note: this term is an adjective, not a noun - i.e. 'a transgender person,' NOT 'a transgender.'
Transsexual: 1) sometimes used to describe a person who has gone through a gender transition involving medical intervention Note: often understood as an outdated and offensive term.
Tucking: the practice of concealing the appearance of one's penis and testes using tape, specialized underwear etc.
Two-spirit: an umbrella term for American Indian indigenous gender identities that extend beyond the male/female binary.
Pansexual: a person who experiences attraction to people of all genders, multiple genders, or regardless of gender. Sometimes used interchangeably with 'bisexual.'
Queer: 1) a historically derogatory term that has been intentionally reclaimed and celebrated by some members of the LGBTQIA+ community. 2) an umbrella term for LGBT people that does not rely on a gender binary. 3) sometimes associated with queer theory (an intellectual tradition that understands gender and sexuality as inherently fluid and unstable categories) or a set of political commitments (i.e. dismantling systems of oppression based on identity).
QTPOC: an abbreviated term for queer and trans people of color.