quarantine flag

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.

quarantine flag

noun

1. 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 Also calledyellow flagyellow jack

Word History and Origins

Origin of quarantine flag¹

First recorded in 1870–75

Example Sentences

Workers arriving in town must be quarantined for 14 days — either in a facility or on a ship, with a yellow-and-black quarantine flag raised.

From New York Times

Quarantin′able, admitting of, or controlled by, quarantine.—Quarantine flag, a yellow flag displayed by a ship to signify the presence on board of contagious disease.

From Project Gutenberg

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

From Time Magazine Archive

The Eastern Star lay no great distance from us, with the quarantine flag flying from her main, and her Jack half-way up her peak.

From Project Gutenberg

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

From Project Gutenberg