noun

• A source of brightly burning light or intense heat.
  "Flare stacks are used in gas plants, petroleum refineries, and petrochemical plants to combust surplus hydrocarbons to produce combustion products that are neither toxic nor combustible. Flares frequently incorporate a liquid-gas separator at the base of the stack and steam assisted burner nozzles at the top of the stack to aid complete combustion."
• (figuratively) A sudden eruption or outbreak; a flare-up.
  "Antiinflammatory corticosteroid creams and ointments are prescribed for inflamed or lichenified areas. These creams are more effective when applied to damp skin. The lowest potency that controls signs should be used, and topical steroids are usually reserved for treatment of episodic flares."
• A widening of an object with an otherwise roughly constant width.
• (in the plural) Bell-bottom trousers.
  "In the early 1970's, a giddy epoch in men's fashion, when denim flares and platform oxfords were the outer edge of style, Giorgio Armani made a suit that stretched. Imbued with spandex, the elastic fiber that gives a fabric extra bounce, the suit was one of the first in a long line of innovations that would eventually make Armani as familiar a brand as Kleenex."

verb

• (transitive) To cause to burn; in particular, to burn off excess gas.
  "Qatar joined the World Bank's Global Gas Flaring Reduction programme in early 2008, indicating its commitment to reducing the process of flaring the gas found with oil deposits."
• (transitive) To cause inflammation; to inflame.
  "Trying to draw a breath flared the pressure on his chest into searing agony."
• (ambitransitive) To open outward in shape.
  "The cat flared its nostrils while sniffing at the air. (transitive)"
• (ambitransitive, aviation) To (operate an aircraft to) transition from downward flight to level flight just before landing.
  "After a brief refueling stop in Fairbanks, Billy continued on to the cabin. As he flared the Huey [a helicopter] to land, he could see Moses running out of the cabin to greet him"