The little square gap between the top of some girls' thighs.

Most girls' thighs come together in a point before the pelvic girdle, but chicks who are particularly trim will have a small, square gap between their thighs.

That is Hogan's Gap. Can be abbreviated simply to Hogan.

Referring to women who are sexually or romantically attracted to other women. Applies to both lesbians and bisexual women, as it is only the same-sex attraction that matters, not any other attractions the women may have.

Originates from the Greek poet Sappho, a bisexual woman from the Isle of Lesbos, from which we get the term lesbian.