cathode, n. (also kathode) Electr.
1 the negative electrode in an electrolytic cell or electronic valve or tube.
2 the positive terminal of a primary cell such as a battery (opp. ANODE).
cathode ray a beam of electrons emitted from the cathode of a high-vacuum tube. cathode-ray tube a high-vacuum tube in which cathode rays produce a luminous image on a fluorescent screen.
cathodal adj. cathodic adj.
Gk kathodos descent f. kata down + hodos way