A straight line is a piece of paper or a board that is completely vertical and horizontal. When Bingo players see a straight line, they know they have hit the number called. The game of Bingo is played with a board with numbered squares. Players try to match the numbers called in a row, column, or both.
When a player finds the number called, they mark off the square on their card with a pencil. If they are playing with another person, that player then takes their turn and tries to match the number called. If they are able to mark off the number called on their card, then they can claim the winnings for that row, column, or both.