RAYS

Rays is a term used across several disciplines to describe a straight, directional line or beam. In geometry, a ray is a part of a line that begins at a fixed point, called its endpoint, and extends infinitely in one direction. It contrasts with a line, which has no endpoints, and with a line segment, which has two endpoints.

In optics and physics, a light ray is a simplified representation of the path along which light travels. Ray diagrams are used to analyze reflection, refraction, and imaging in lenses and mirrors. While light itself has wave and particle properties, the ray model provides a convenient abstraction for predicting directions and focusing effects.

The word ray is also common in discussions of electromagnetic radiation. X-rays, gamma rays, and other high-energy forms of light are often referred to as rays. In radiography and medical imaging, X-rays are used to view internal structures. In particle physics and astronomy, the term can extend to beams of particles or to the concept of cosmic rays—high-energy particles arriving from outer space.

In biology, rays are a group of cartilaginous fishes within the superorder Batoidea, including stingrays, manta rays, electric rays, and eagle rays. They typically have flattened bodies with enlarged pectoral fins fused to the head, gill slits on the underside, and a whip-like tail. Many species are marine, some are benthic, and several possess stinging spines for defense.

Rays also appear in everyday language to describe beams of light or sunlight and other directional emissions, such as rays of sunshine or meteorological sunbeams.