quarantine flag

American  

noun

Nautical.

1. a yellow flag, designating the letter Q in the International Code of Signals: flown by itself to signify that a ship has no disease on board and requests a pratique, or flown with another flag to signify that there is disease on board ship.

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quarantine flag British  

noun

1. Also called: yellow flag.   yellow jack.  nautical the yellow signal flag for the letter Q, flown alone from a vessel to indicate that there is no disease aboard and to request pratique or, with a second signal flag, to indicate that there is disease aboard

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Etymology

Origin of quarantine flag

First recorded in 1870–75

Example Sentences

It is advisable to fly a yellow quarantine flag as you enter the Bahamas until you�ve cleared customs.

From Time Magazine Archive

At her mizzen-peak flew the American ensign, and at the fore-truck the ominous quarantine flag.

From The Tale of Timber Town by Grace, Alfred A. (Alfred Augustus)

Why did he not at this time hoist his quarantine flag and warn every one that he was dangerous to come near?

From The Oxford Movement Twelve Years, 1833-1845 by Church, R. W. (Richard William)

"Miss Carstow," she prompted, in a voice that seemed to raise a quarantine flag above him.

From The Lighted Match by Schabelitz, R. F.

She was flying two flags—an inverted ensign and the yellow quarantine flag.

From Cappy Ricks Retires by Kyne, Peter B. (Peter Bernard)