cathode-ray

The term 'cathode-ray' is a modern scientific compound formed in the late 19th century. 'Cathode' originates from the Greek 'kathodos', literally meaning "a way down," which was adopted by scientist Michael Faraday to designate the electrode where current exits a device (conceived as a downward path). 'Ray' descends from the Latin 'radius', meaning a spoke or beam, which evolved to describe lines of light or energy. When combined, the term logically denotes a stream of electrons (the "ray") emanating from the negatively charged electrode (the "cathode") in a vacuum tube, linking the ancient concepts of a downward path and a projected beam to describe a fundamental phenomenon in physics and electronics.

Structure: cathode + ray cathode: From Greek 'kathodos' (a way down, descent), from 'kata-' (down) + 'hodos' (way, path). In this compound, it functions as a noun specifying the source of the emission. ray: From Old French 'rai', from Latin 'radius' (spoke of a wheel, beam of light). In this compound, it functions as a noun denoting a stream of particles or radiation.