Gay: a common synonym for homosexual (most often male).
Heterosexism: privileging heterosexuality as a dominant cultural institution over minority sexualities.
Heterosexual: a person who chooses sexual partners of the opposite gender.
Homophobia: a fear of homosexuality in which there is contempt and/or hatred for homosexuals.
Homosexual: a person who chooses sexual partners of the same gender
Lesbian: common synonym for female homosexuals.
Transgendered: a term often applied to masculine lesbians or effeminate men who are androgynous psychologically and/or physically.
LGBT: An initialization of Lesbian, Gay, Bi-Sexual, and Transgender which is an encompassing sexuality and gender identity-based groups and is often used to refer to anyone who is not heterosexual.
Queer: a umbrella term encompassing LBGT groups.