the.com/solar flare

means A sudden, intense burst of radiation from the sun's surface, released when magnetic energy built up in the atmosphere around sunspots suddenly snaps and discharges.

from Straightforward scientific compounding: 'solar,' from Latin 'sol' (sun), joined to 'flare,' an English word for a sudden blaze of light or fire, used since the 1600s for flames that leap up briefly before settling. Astronomers borrowed that everyday sense of 'flare'—a quick, bright flash—once telescopes and later spectroscopes let them watch the sun's surface erupt in sudden brightenings. The term solidified in the early 1900s as solar observation matured into a real science, giving a plain, descriptive name to a genuinely explosive event.