BYOB's an initialism most commonly meant to stand for "bring your own bottle". BYOB may also be defined as "bring your own beer" or "bring your own booze". The term "booze"'s slang for alcoholic drinks. Possibly for a more generic situation, it could be "bring your own beverage." It's also commonly used to mean "bring your own beef" at a barbecue. BYOB's often placed on an invitation to indicate that the host won't be providing alcohol and that guests are welcome to bring their own. It's also f… (More on Byob)