What is the origin of the phrase spot on?

Answer 1

The phrase 'spot on', meaning 'in exactly the right place, comes to us from India and the snooker-based game of billiards The six coloured balls were each placed on their respective 'spots' on the table after having been sunk The placement of these coloured balls, unlike the red balls, which were permanently 'sunk' when potted, was critical to the game, so the person re-spotting the coloured balls (other than red, of course) would have to be precisely on the correct spot, or, 'spot on' for the game to be fairly played The critical nature originated from the size of the table; 6' x 12', and the tightness of the pockets; 1.5 x ball diameter, unlike today's 'sloppy' 2 x ball diameter