As per Wikiepdia, “LGBT (or GLBT) is an initialism stands for lesbian, gay, bisexual, and transgender. In use since the 1990s, the term is an adaptation of the initialism LGB, which was used to replace the term gay in reference to the LGBT community beginning in the mid-to-late 1980s. Activists believed that the term gay community did not accurately represent all those to whom it referred.”

“Q” was added to the term in 1996, according to Wikipedia, and stands for “queer” or “questioning.”

See stories on LGBTQ-related topics here.