Yellow flag Meaning, Definition & Usage

  1. noun common yellow-flowered iris of Europe and North Africa, naturalized in United States and often cultivated
    Iris pseudacorus; yellow iris; yellow water flag.

WordNet


Definitions
  1. the quarantine flag. See under Quarantine, and 3d Flag.
Definitions
  1. the quarantine flag of all nations; also carried at a vessel's fore, to denote that an infectious disease is on board.

Webster 1913