blue peter

American  

noun

Nautical.

1. a blue flag with a white square in the center, designating the letter P in the International Code of Signals, flown by a vessel in port to indicate its imminent departure.

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blue peter British  

noun

1. a signal flag of blue with a white square at the centre, displayed by a vessel about to leave port

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Etymology

Origin of blue peter

First recorded in 1815–25

Example Sentences

A blue peter is a blue flag with a white square in the center, and it is flown when a ship is ready to sail.

From "Silent To The Bone" by E.L. Konigsburg

Outside the bar, her two anchors down, the blue peter at her fore, and the English Union Jack floating at her gaff, rode the brig “Halcyon.”

From The Ruined Cities of Zululand by Walmsley, Hugh Mulleneux

All too soon the blue peter at half-mast and the blowing of the hooter recalled them.

From The Bonadventure A Random Journal of an Atlantic Holiday by Blunden, Edmund

Ay, by Jupiter, there goes the very blue peter I helped to make with my own hands, and it was agreed to set it, as the deacon's signal.

From The Sea Lions The Lost Sealers by Cooper, James Fenimore

Her flags were hoisted, the blue peter fluttering at the fore, and the Active tug was passing a hawser aboard, getting ready to tow her out.

From Great Sea Stories by French, Joseph Lewis