BYOB or BYO is an initialism and acronym concerning alcohol that means "bring your own bottle" or "bring your own booze" or "bring your own beer". BYOB is stated on an invitation to indicate that the host will not be providing alcohol and that guests should bring their own. Some restaurants and business establishments (especially in areas where liquor licenses are difficult to obtain) allow patrons to bring their own bottle, sometimes subject to fees or membership conditions, or because the establishment itself does not have license to sell alcohol. Etymology Today, BYOB may mean "bring your own bottle" or "bring your own booze". BYOB is a later variant of the earlier expression, BYOL, meaning "bring your own liquor." The earliest known examples of BYOL appeared in two panels of a cartoon by Frank M. Spangler in the Montgomery Advertiser (Montgomery, Alabama), December 26, 1915, page 5. The joke was that a man received an invitation with the mysterious letters "BYOL" in place of RSVP. He looked up the initials in a "social directory" and learned that it stood for "Bring Your Own Liquor". Other early examples of the expression appeared in newspapers in Alabama or stories relating to Alabama, suggesting that it may have originated there, perhaps coined by Spangler himself. At the time, Alabama had recently enacted a new statewide prohibition law prohibiting the sale, but not the consumption of alcohol, making it necessary to bring one's own alcohol. A variant of BYOB is BYOS, meaning "bring your own sugar". This was used in England and the United States amid wartime rationing during World War I and again in World War II. Shortly after passage of the Eighteenth Amendment to the United States Constitution prohibiting the sale of alcohol nationwide, a joke about BYOL replacing RSVP on formal invitations began circulating in newspapers across the country. The joke appeared as early as June 1919 in the Des Moines (Iowa) Daily News, and was in wide circulation by the end of the year. BYOB appeared occasionally during the 1920s, and when defined was usually rendered as "bring your own booze", although "beer", "bottle" and "beverage" were all suggested on at least one occasion. BYOL was the dominant form of the expression until the 1950s. But when BYOB became more popular in the 1950s, it was regularly defined as "bring your own bottle", frequently in circumstances involving restaurants without liquor