What does anode mean?
An anode is one of the two electrodes found in devices that conduct electricity through ions or charged particles, such as batteries, electrolytic cells, vacuum tubes, and diodes. By convention, the anode is the electrode at which conventional (positive) current enters a device from the external circuit, while its counterpart, the cathode, is where current exits. In practical terms, this means the anode is typically the negative terminal of a discharging battery but the positive electrode in an electrolytic cell — a reversal that often puzzles learners. Chemically, the defining feature of an anode is that oxidation occurs there: atoms lose electrons. The word appears most often in technical writing about electronics, corrosion protection, and industrial chemistry. A familiar application is the sacrificial anode, a piece of reactive metal placed in water heaters or ship hulls to corrode preferentially and thereby protect more valuable components from rust and decay.
nounThe positively charged electrode of an electrical device, such as a battery or vacuum tube, toward which electrons flow from outside the circuit. In electrolysis and electroplating, it is the electrode at which oxidation occurs.
- The positive electrode in a battery, vacuum tube, or other electrical device, at which conventional current enters.
- The electrode at which oxidation occurs during electrolysis or electroplating.
"The technician replaced the corroded anode in the water heater to prevent further tank damage."
"Electrons flow from the anode to the cathode through the external circuit when the battery discharges."
"During electrolysis of molten sodium chloride, chlorine gas is released at the anode."
Standard English plural; commonly used when discussing multiple electrodes in a battery pack or industrial cell.
"Each of the three cells in the battery contains its own anode and cathode."
In a battery, the anode is actually where electrons leave — so despite being 'positive,' it's the source of the electron flow that powers your phone.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of anode
The word 'anode' was coined in the early nineteenth century by Michael Faraday, working with William Whewell, as part of the terminology they developed for describing electrolysis. It derives from the Greek 'anodos', meaning 'way up' or 'ascent' (from 'ana-', up, plus 'hodos', way), reflecting the upward path of the electric current as then conceived. Its direct counterpart, 'cathode', comes from the Greek 'kathodos', meaning 'way down'. Faraday's related coinages include 'ion', 'electrode', and 'electrolyte', all drawn from Greek roots he and Whewell selected for the new science of electrochemistry.
How anode is actually used
A technical term used primarily in physics, chemistry, and engineering contexts; rarely encountered in everyday conversation. Note that the polarity assigned to the anode depends on whether the device is galvanic (discharging) or electrolytic (charging), which can cause confusion even among students of science.
Easily confused with anode
The cathode is the negatively charged electrode through which conventional current leaves a device, whereas the anode is the positive electrode where conventional current enters — though in electrolytic cells their polarities are reversed.