The term anode, from the Greek words hodos, meaning way, and ana, meaning up, was used by experimenters in the late ninteenth and early twentieth century to designate the conducting to which negatively charged particles, electrons, were drawn when they subjected partially evacuated tubes to high voltage. The tubes were made of glass and typically had a voltage source connected to two pieces of conducting materials sealed into the glass and separated by a few inches. The piece of conducting material from which the electrons emanated was called the cathode and the one to which they were attracted was called the anode.

In chemistry the most common use of the term anode occurs in electrochemistry. Electrochemical cells consist of one half-cell in which oxidation occurs and a second half-cell in which reduction occurs. Electrons flow though a conductor connecting the two half-cells. At the two ends of the...