Opening to an explanation, typically a contradiction, where the speaker is implying in a none-too-subtle manner that the other person could well be among the stupidest person in existence (ever) for not knowing this.

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.