For the purposes of this wiki and the IAGSDC, LGBTQ* refers to Lesbian, Gay, Bisexual, Transgender, Queer, Questioning, Intersex, and their friends.
The IAGSDC bylaws were amended in 2012 to replace "Lesbian and Gay" as well as all uses of just the term "gay" in the text with LGBTQ*.
"GLBT", "LGBT" and other variants are also in common use.
Wikipedia on "LGBT" 
WikiQueer on "LGBT" 
LCFD tips on being more trans-aware and trans-inclusive Trans Ally 101
UC Davis LGBT Center page on Trans-phobia 
New York Times article on millennials and LGBTQIA alphabet soup