| 1. | the symbol or banner of a left-wing revolutionary party. |
| 2. | a danger signal. |
| 3. | something that provokes an angry or hostile reaction: The talk about raising taxes was a red flag to many voters. |
| 4. | Also called powder flag. Nautical. a red burgee, designating in the International Code of Signals the letter “B,” flown by itself to show that a vessel is carrying, loading, or discharging explosives or highly inflammable material. |
| 5. | (initial capital letters) a war game the U.S. Air Force holds several times each year at Nellis Air Force Base, Nevada, to train personnel in air combat. |