A flare, also sometimes called a fusée, fusee, or bengala, bengalo in several European countries, is a type of pyrotechnic that produces a bright light or intense heat without an explosion. Flares are used for distress signaling, illumination, or defensive countermeasures in civilian and military applications. Flares may be ground pyrotechnics, projectile pyrotechnics, or parachute-suspended to provide maximum illumination time over a large area. Projectile pyrotechnics may be dropped from aircraft, fired from rocket or artillery, or deployed by flare guns or handheld percussive tubes.

The earliest recorded use of gunpowder for signaling purposes was the 'signal bomb' used by the Chinese Song Dynasty (960–1279) as the Mongol-led Yuan Dynasty (1271–1368) besieged Yangzhou in 1276. These soft-shelled bombs, timed to explode in midair, were used to send messages to a detachment of troops far in the distance. Another mention of the signal bomb appears in a text dating from 1293 requesting their collection from those still stored in Zhejiang. A signal gun appears in Korea by 1600. The Wu I Thu Phu Thung Chih or Illustrated Military Encyclopedia, written in 1791, depicts a signal gun in an illustration.

In the civilian world, flares are commonly used as signals, and may be ignited on the ground, fired as an aerial signal from a pistol-like flare gun, or launched from a self-contained tube. Flares are commonly found in marine survival kits.

Distress rockets (aka "rocket-propelled parachute flares") have been mentioned in the modern era for civilian maritime emergencies since at least 1856. The U.S. Nautical Magazine of that year mentions the use of "rocket stations" for ship related emergencies. White rockets were solely used until 1873, when commander John Yorke of the Royal Navy suggested that rockets for distress should have a distinctive color. The request was made to help ease confusion between ships in distress and rockets used by pilot ships. By 1875, the UK Board of Trade had issued regulations for captains in regards to night signals. Rockets containing at least 16oz of composition were only to be used as a sign for a ship in distress. Passenger ships at the time were required to carry 12 of these rockets. The Merchant Shipping Act 1894 further stated that these rockets were to be fired one at a time in short intervals of approximately one minute apart. Distress rockets continued to be used in different colors, as was the case with RMS Titanic. At the time shipping companies had "a particular kind of distress rocket (that differed by color)". Each ship was also given a guide of colors to use depending on what signal was to be sent.

Modern red distress signals are mentioned by the United States Bureau of Mines as early as 1959, where they state "12 handheld rocket-propelled parachute red flare distress signals" are to be used by ocean going ships. The color red was eventually incorporated for use in the United States on 17 December 1979 as part of a "Universal color language". Red distress rockets and/or flares are now internationally recognized symbols that indicate a ship in distress. The International Convention for the Safety of Life at Sea (SOLAS) has standards for visual signals, including both handheld and aerial flares. Handheld flares must burn for at least one minute at an average luminosity of 15,000 candelas, while aerial flares must burn for at least 40 seconds with a 30,000-candela average luminosity.

While rockets and flares are still an option for signaling distress, they have since been surpassed by improved technology. Distress signals can now be sent using automated radio signals from a search and rescue transponder. Other internationally recognized methods include the radio message SOS, which was used during the 1912 sinking of the Titanic, and the emergency procedure word "Mayday", which dates to the 1920s.

Another type of flare is the fusee, which burns with a bright red light. These come in two main types which are used for roadways and rail transportation. The first type are fusees used for roadways which are known as highway flares or road flares. These are commonly used to indicate obstacles or advise caution on roadways at night and are found in roadside emergency kits. Law enforcement also may use these flares (either propped on a biped or laid flat) to signal traffic hazards or that a road is blocked, often as a more visible replacement for traffic cones. Law enforcement in the United States usually use magnesium-based flares that last from 15–30 minutes.

Fusees used for rail are known as railroad flares, they are commonly used to perform hand signals or used as torches in rail transport applications. Railroad flares can burn for at least 10 minutes, are not fastened to train cars, and are handheld by railroad personnel for protection at night. It was argued during an Appeals case that railroad flares are much more visible than lanterns. In general: trains that encounter a lit railroad flare are required to stop until it burns out. Fusees made specifically for railroad use can be distinguished from highway fusees by a sharp steel spike at one end, used to embed the fusee upright in a wooden railroad tie.