This idiom means something is honest, transparent, and conducted openly without deceit or hidden motives. It suggests fairness and legitimacy, often used in business, negotiations, or personal dealings to emphasize trustworthiness and adherence to rules.

The phrase comes from 17th-century card games, where players kept their hands ‘above the board’ (table) to show they weren’t cheating by hiding cards. An early use appears in Henry Hammond’s 1648 *Sermons*: ‘All fair and above board.’ By the 18th century, it was a common metaphor for honesty, as seen in Jonathan Swift’s writings. Its nautical associations, linked to shipboard activities, also reinforced its sense of openness, and it became standard in British and American English by the 19th century.