Red flag (signal)
Encyclopedia
Red flag is a semi-official term to denote various attention and awareness indicators and signals, both explicit and implicit. It can be used in various contexts usually as a warning or when things seem too good to be true as well as unexpectedly good results.
The earliest citation for "red flag" in the Oxford English Dictionary is from 1602 and shows that at that time the flag was used by military forces to indicate that they were preparing for battle.1602 Dekker Satirom. Wks. 1873 I. 233 What, dost summon a parlie, my little Drumsticke? tis too late: thou seest my red flag is hung out.
1666 Lond. Gaz. No. 91/4 That the Red Flag was out, both Fleets in sight of each other, expecting every hour fit weather to Engage.
The earliest citation of "red flag" in the sense of a warning is dated 1777 and refers to a flag warning of flood.1777 P. Thicknesse Year's Journey I. iii. 23 There is a red flag hoisted gradually higher and higher, as the water flows into the harbour [at Calais].
The term and the expression "to raise the red
flag" come from various usages of real flag
s in real life. The semaphore red flag (or red light) on railways means an immediate stop, while a red flag is frequently flown by armed forces to warn the public of live fire exercises in progress, and is sometimes flown by ships carrying munitions (in this context it is actually the flag for the letter B in the International maritime signal flag alphabet
, a red swallow-tailed flag
). In many countries a red flag is flown to signify that an outdoor shooting range
is in use. The United States Air Force
refers to its largest annual exercise
as Operation Red Flag. Red flags are used for various signals in team sailing races (see Racing Rules of Sailing
). A red flag warning
is a signal of high wildfire danger and a red flag on the beach warns of dangerous water conditions (double red flags indicate beach closure). Red flags of various designs indicate dangerous wind and wave conditions for mariners. In auto racing, a red flag indicates a stop to the race due to dangerous conditions.
A signal of danger
or a problem can be referred to as a red flag, a usage that originated in the 18th century. The term "red flag" is used, e.g., during screening of communications, and refers to specific words or phrases encountered that might indicate relevance to the case. For example, email spam filters make use of such "red flags".
The earliest citation for "red flag" in the Oxford English Dictionary is from 1602 and shows that at that time the flag was used by military forces to indicate that they were preparing for battle.1602 Dekker Satirom. Wks. 1873 I. 233 What, dost summon a parlie, my little Drumsticke? tis too late: thou seest my red flag is hung out.
1666 Lond. Gaz. No. 91/4 That the Red Flag was out, both Fleets in sight of each other, expecting every hour fit weather to Engage.
The earliest citation of "red flag" in the sense of a warning is dated 1777 and refers to a flag warning of flood.1777 P. Thicknesse Year's Journey I. iii. 23 There is a red flag hoisted gradually higher and higher, as the water flows into the harbour [at Calais].
The term and the expression "to raise the red
Red
Red is any of a number of similar colors evoked by light consisting predominantly of the longest wavelengths of light discernible by the human eye, in the wavelength range of roughly 630–740 nm. Longer wavelengths than this are called infrared , and cannot be seen by the naked eye...
flag" come from various usages of real flag
Flag
A flag is a piece of fabric with a distinctive design that is usually rectangular and used as a symbol, as a signaling device, or decoration. The term flag is also used to refer to the graphic design employed by a flag, or to its depiction in another medium.The first flags were used to assist...
s in real life. The semaphore red flag (or red light) on railways means an immediate stop, while a red flag is frequently flown by armed forces to warn the public of live fire exercises in progress, and is sometimes flown by ships carrying munitions (in this context it is actually the flag for the letter B in the International maritime signal flag alphabet
International maritime signal flags
The system of international maritime signal flags is one system of flag signals representing individual letters of the alphabet in signals to or from ships...
, a red swallow-tailed flag
Swallowtail (flag)
In flag terminology, a swallowtail is either# a V-shaped cut in a flag that causes the flag to end in two points at the fly; or# any flag which has this V-shaped cut....
). In many countries a red flag is flown to signify that an outdoor shooting range
Shooting range
A shooting range or firing range is a specialized facility designed for firearms practice. Each facility is typically overseen by one or more supervisory personnel, called variously a range master or "RSO – Range Safety Officer" in the United States or a range conducting officer or "RCO" in the UK...
is in use. The United States Air Force
United States Air Force
The United States Air Force is the aerial warfare service branch of the United States Armed Forces and one of the American uniformed services. Initially part of the United States Army, the USAF was formed as a separate branch of the military on September 18, 1947 under the National Security Act of...
refers to its largest annual exercise
Military exercise
A military exercise is the employment of military resources in training for military operations, either exploring the effects of warfare or testing strategies without actual combat...
as Operation Red Flag. Red flags are used for various signals in team sailing races (see Racing Rules of Sailing
Racing Rules of Sailing
The Racing Rules of Sailing govern the conduct of yacht racing, windsurfing, kitesurfing, model boat racing, dinghy racing and virtually any other form of racing around a course with more than one vessel while powered by the wind...
). A red flag warning
Red flag warning
A Red Flag Warning is a forecast warning issued by the United States National Weather Service to inform area firefighting and land management agencies that conditions are ideal for wildland fire ignition and propagation...
is a signal of high wildfire danger and a red flag on the beach warns of dangerous water conditions (double red flags indicate beach closure). Red flags of various designs indicate dangerous wind and wave conditions for mariners. In auto racing, a red flag indicates a stop to the race due to dangerous conditions.
A signal of danger
Risk
Risk is the potential that a chosen action or activity will lead to a loss . The notion implies that a choice having an influence on the outcome exists . Potential losses themselves may also be called "risks"...
or a problem can be referred to as a red flag, a usage that originated in the 18th century. The term "red flag" is used, e.g., during screening of communications, and refers to specific words or phrases encountered that might indicate relevance to the case. For example, email spam filters make use of such "red flags".