Flare means to burn suddenly with a bright, unsteady light, or to burst outward in a widening shape.

When a match flares up, it creates a sudden bright flame. A campfire might flare when you add dry leaves, sending up a quick burst of light and heat. Ships in distress shoot flares into the sky: these are special rockets that burn brilliantly so rescuers can spot them from far away.

The word also describes things that spread outward. Pants with flared legs get wider from the knee down, like a bell. A trumpet's end flares outward. Your nostrils might flare when you're angry or breathing hard.

People use flare to describe sudden outbursts too. Someone's temper might flare during an argument, or an old injury might flare up after exercise. Scientists talk about solar flares, which are massive explosions of energy on the sun's surface.

The word captures that sense of something sudden, bright, and spreading outward, whether it's actual fire, a widening shape, or an intense emotion that bursts forth unexpectedly.