View your list of saved words. (You can log in using Facebook.)
Terminal or electrode at which electrons enter a system, such as an electrolytic cell or an electron tube. In a battery or other source of direct current, the cathode is the positive terminal. In a passive load it is the negative terminal. In an electron tube, such as a cathode-ray tube, electrons stream off the cathode and travel through the tube toward the anode.
This entry comes from Encyclopædia Britannica Concise. For the full entry on cathode, visit Britannica.com.