The term queer is commonly used as an umbrella term for members of the lesbian, gay, bisexual, and transgender (LGBT) communities. Some individuals who do not identify closely with any of these terms but who also do not identify as heterosexual and cisgender choose the term queer as their identity descriptor. “Queer” is a nonspecific descriptor, which may refer to sexual orientation, gender identity, sexual practices, or some combination of these factors. In the common abbreviation LGBTQ, the Q typically stands for “queer” (although it previously referred to “questioning”). This entry discusses the history of the use of the term as well as related queer theory.