Blue and white flag for the letter "P".
A blue signal flag with white square in the center, hoisted on the foremast to indicate a vessel is ready to sail. It was a recall to the crew "that they repair on board" and for shoresiders to conclude any business they had with the vessel.
A blue flag with an oblong white center, indicating a ship is about to sail when hoisted, at different periods, at the foremast or mainmast. Its name is said to derive from the French verb partir, to leave; or from Sir Peter Parker (1783), Admiral Cornwallis, known as "Billy Blue"; a corruption of "blue pierced"; or from "peter", an old name for a cabin trunk. Take your pick
a blue flag with a white square in the center indicates that the vessel is ready to sail
a blue flag with a white square at the center of it
Naval The common nautical name for flag - blue with white central square - worn by merchant ships (not R.N. ships) when about to leave port, warning all persons concerned to get on board without delay.
Letter P of the international code. It is a blue square flag with a white square in the centre, hoisted on the mast to indicate that the vessel is about to sail.
A blue and white flag hoisted at the foretrucks of ships about to sail.
Blue Peter is a popular, long-running BBC television programme for children, and airs on Children's BBC (CBBC) . It is named after the blue-and-white flag hoisted by ships in port when they are ready to sail. The reasoning behind the choice of title is that the programme is intended to be a voyage of adventure and discovery for the viewers, constantly covering new topics.
Blue Peter (1936-1957) was a British Thoroughbred racehorse whose career was cut short by the outbreak of World War II.