Cisgender

an adjective for someone whose gender corresponds to their assigned sex

I am perfectly comfortable identifying as the gender my parents put on my birth certificate. I am cisgender.

Gender

one’s internal sense of self in relation to the social constructs of masculinity, femininity and androgyny

Sam is a boy. That is his gender.

Transgender

an adjective for someone whose gender does not correspond, or does not fully correspond, to their assigned sex.

Laverne Cox is transgender.