We use the term Across The Board to suggest something all encompassing and wide-ranging. At race meetings from the 19th century large boards were used to display the odds on horses to come first, second or third. It was common to bet an even amount of money on one horse to finish first, second or third. This was known as an “across the board bet”. Due to how the bookmaker’s odds were calculated it was uncommon to win more than the sum of the three bets.