The clubhouse bar — golf's affectionate name for the unofficial stop that follows the eighteenth green. The joke is nearly as old as the standardized 18-hole round: Scottish newspapers were praising the enthusiasm shown "at the 'nineteenth' hole" by 1890, and an 1891 English paper noted that where the nineteenth takes the shape of a public-house, players always negotiate this hole at the first attempt. It crossed the Atlantic by 1899, when a New York captain located Van Cortlandt Park's nineteenth "across the way in Sullivan's." The tradition is the point: the round isn't quite over until the stories have been told, the presses settled, and the day's one pure strike relived. Indoors, the nineteenth is conveniently ten steps from the bay.
Source: https://wordhistories.net/2021/02/09/nineteenth-hole/ · high confidence