Quarantine flag

From Fresh Dictionary

English

Noun

quarantine flag

1. ((nautical{{#if:|, {{{2}}}{{#if:|, {{{3}}}{{#if:|, {{{4}}}{{#if:|, {{{5}}}{{#if:|, {{{6}}}{{#if:|, {{{7}}}{{#if:|, {{{8}}}{{#if:|, {{{9}}}}}}}}}}}}}}}}}}})) a yellow flag hoisted by all ships on entering a harbor, to show that it has contagious or infectious disease aboard, or by a ship that has been quarantined