Rayo

Rayo is a Spanish noun meaning ray or beam, and it covers several related ideas in science, language, and culture. In geometry and physics, un rayo refers to the portion of a line that starts at a fixed point and extends infinitely in one direction. In everyday language and optics, it denotes a beam or streak of light, as in un rayo de sol (a sunbeam) or un rayo de luz (a beam of light). In meteorology and common usage, rayo also designates a bolt of lightning. In medical imaging and radiography, the term appears in rayos X, the X-ray beams used for diagnostic imaging; the plural rayos X is standard in Spanish.

Etymology: Rayo comes from Latin radius, meaning spoke, beam, or ray, and entered Spanish with senses related to lines emanating from a source.

Usage as a proper noun: Rayo Vallecano, a Madrid-based football club, is widely known by the nickname “Rayo.” The term also appears in personal names and various place names in the Spanish-speaking world, reflecting its strong association with light and direction.

See also: Ray. In other Romance languages, cognate terms exist with similar meanings, illustrating the shared idea of a line or beam emanating from a point.