ray

Ray is a term with several related but distinct meanings. In geometry, a ray is a part of a straight line that begins at a fixed point, called the endpoint or origin, and extends indefinitely in one direction. It is distinguished from a line, which extends in both directions, and from a line segment, which is finite.

In physics and optics, 'ray' describes the path along which light or other radiation travels. A light ray is the straight-line path that light follows in a uniform medium. The concept underpins ray optics and is used in devices such as lenses and mirrors. In computer graphics, ray tracing is a rendering technique that simulates the way rays of light interact with surfaces to produce realistic images.

The name Ray is used as a given name and surname. It may be derived from Raymond. Notable individuals include Ray Charles, American musician and pianist; Ray Bradbury, American writer; Ray Romano, American actor and comedian; and Ray Dalio, American investor and founder of Bridgewater Associates.

In biology, the term ray also refers to certain cartilaginous fishes known as rays, including manta rays and stingrays. These animals are elasmobranchs related to sharks and are characterized by flattened bodies and enlarged pectoral fins that resemble wings.

In other contexts, 'ray' appears in terms such as X-ray, gamma ray, or sunlight rays, referring to specific types or beams of electromagnetic radiation. The term can also describe a narrow beam or fissure in various materials or natural formations.