Bisexual - Someone who is attracted to both males and females. Some people prefer the terms omnisexual or pansexual instead, because "bi" means two, and there actually are more sexes than two.

Breeder - A derogatory term for a heterosexual or occasionally bisexual.

Butch - A masculine woman, usually a lesbian.

Camp - A form of humor popular among queers of many kinds. Camp is highly satirical, sometimes to the point of meanness.

Circuit party - One of several parties scattered around the country that are held to raise money for AIDS research. Circuit parties are sometimes criticized because of the amount of unsafe sex and drug use that supposedly goes on at them.

Closet case - A gay person who spends most of his or her life in the closet and is extremely worried about it because he or she is scared of being outed.

Coming out - To "exit the closet" by becoming openly gay.

Drag queen - A gay man who dresses as a woman for pleasure and/or performance. It is usually polite to refer to a drag queen as "she" when she is in drag, and "he" when he is not.

Fag hag - A person, frequently a straight woman, who greatly enjoys spending time with gay men.

Femme - A feminine woman, usually a lesbian; a feminine gay man or drag queen.

Gay - Homosexual. The term originated as a code word for homosexuals when queer became too well-known. Previous to this usage, "gay" or "gey" had been used since at least Victorian times to refer to sex, usually of an illicit or publicly disapproved-of variety. "Geying it up" once meant visiting a brothel.

Gaydar - "Gay radar," the sense through which gays are identified by others in the gay community.

GLBT - Gay, lesbian, bisexual, transgender/transsexual.

Heterosexism - The belief that heterosexuality is superior to homosexuality or bisexuality, or the tendency to assume that everyone is heterosexual.

Homophobia - An extreme irrational hatred or fear of homosexuals.

Intersexed - A person born with ambiguous genitalia. Thousands of babies every year are born with ambiguous genitalia, and are frequently reshaped by surgeons, often without the parents' consent or even knowledge. These operations can result in emotional trauma to the child, and loss of sensation and orgasmic ability.

Lesbian - A homosexual woman. The word derives from the Greek island of Lesbos, where the poetess Sappho ran a school for young women, and wrote often erotic poetry about love between women. She is considered by many lesbians to have been a lesbian, although she was married and had children.

Out - Publicly known as gay, sometimes modified with "very"; known as gay to close friends and/or blood family; acknowledgement to oneself that one is gay.

Outed - Having it announced publicly that one is gay by someone other than oneself, usually when one would rather stay in the closet. Outing has recently come into use as a political weapon.

Pink triangle - The symbol gay men were made to wear in the Nazi concentration camps. It became a symbol of gay pride, and was first used to remind some homophobic Jews that homosexuals were in the concentration camps, too.

Pride - The belief that Gay is Good!, used in titles of events to denote that they are gay celebrations.

Queen - A drag queen; a flamboyant, effeminate gay man.

Queer - Gay, lesbian, bisexual, omnisexual, pansexual, transgendered, or transsexual.

Rainbow - A gay pride symbol, designed by Gilbert Baker in 1978, originally having eight stripes: hot pink, red, orange, yellow, green, blue, indigo, and violet, which stood for sexuality, life, healing, the sun, nature or serenity, art, harmony, and spirit. The hot pink stripe was dropped when flag makers couldn't find suitable material, and the indigo stripe was dropped to make the flag more balanced, so that three stripes could hang on either side of lampposts at pride parades.

Transgender - Anyone who crosses gender boundaries, including, but not limited to, transsexuals and transvestites; a person who lives mostly or completely in the gender not associated with their birth sex, but who does not identify as a transsexual.

Transsexual - A person whose birth sex is viewed by hir* as incorrect or incompatible with hir image of hirself, and who takes steps (including but not limited to physical and/or hormone therapy, and surgery) to make hir outer self match hir self-identification.
*=Hir, a contraction of him and her, is the transgender pronoun often used in place of traditional pronouns.

Source: Rebecca Scott, A Brief Dictionary of Queer Slang and Culture