from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. 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
from the GNU version of the Collaborative International Dictionary of English
- n. a yellow flag hoisted at the fore of a vessel or hung from a building, to give warning of an infectious disease; -- called also the yellow jack, and yellow flag.
Sorry, no etymologies found.