yellow flag

noun

Nautical. quarantine flag.
water flag.

Origin of yellow flag

First recorded in 1775–85

Words nearby yellow flag

yellow enzyme, yellow fever, yellow fever vaccine, yellow fever virus, yellow fiber, yellow flag, yellow gentian, yellow goatfish, yellow granadilla, yellow gum, yellow hats

British Dictionary definitions for yellow flag

yellow flag

noun

another name for quarantine flag
See flag 3 (def. 1)