yellow flag 
noun
1A yellow flag flown by a ship to indicate the presence on board of disease.Placards or yellow flags traditionally marked places under quarantine....
- A hatch opened on the top of the ship, revealing a Mulinyan admiral, carrying the red and yellow flag and a voice amplifier.
1.1 Motorsports A yellow flag used to signal to drivers that there is a hazard such as a crashed car ahead.Retirements included Ryan Hunter Reay who crashed heavily on the sixth lap bringing out the yellow flags....
- For this reason use of the safety car should be kept to a minimum, replaced by outright race stoppages or use of double-waved yellow flags.
- But it was nice to be reminded what a checkered flag was, what a [last-lap] white flag was, and no black flags, no yellow flags.
2A yellow-flowered European iris which grows by water and in marshy places.
- Iris pseudacorus, family Iridaceae.
- Once balance is restored, then well-protected shallow margins will be easier to colonise with wetland wildflowers such as flowering rush, yellow flag, marsh marigold and water forget-me-not.
- Rooted into this the plants, such as reeds, water lilies, flowering rushes, Cyperus longus and yellow flag irises, do their job of taking nitrates out of the water and reducing phosphates.
- residentura
- resident withholding tax
- Residenz
- Residenzstadt
- resider
- residua
- residual
- residual body
- residual current
- residual current device
- residual herbicide
- residual hypothesis
- residual legatee
- residually
- residual map
- residual oil
- residual powers
- residual stress
- residual sugar
- residual volume
- residuary
- residuary clause
- residuary devisee
- residuary legatee
- residuary powers