A non-man that loves another non-man. Commonly seen as "woman loving woman," but the spectrum of lesbianism is much broader. People under the trans, non-binary, genderfluid, etc. umbrellas can also identify as a lesbian.
Man: Yooo look at that fem-aligned person over there omg hotsexy Other man: No bro they're a lesbian you gotta respect that
Angel: “How are they a lesbian if they’re nonbinary?”
Zack: “Bro, A Lesbian is a non man attracted to a non man, meaning nonbinarys can be lesbian too!