Definition
A conductor through which electric current enters or leaves a device, circuit, or working medium such as a gas, liquid, or vacuum. In aviation contexts, electrodes appear in spark plugs, batteries, and various sensors, where they form the points at which electrical energy is transferred between the conductor and the surrounding material.
Plain English
A piece of metal that carries electricity into or out of something — like the two metal tips inside a spark plug that the spark jumps between, or the terminals on a battery.
Context Anchor
Pilots most often encounter this word in discussions of aircraft spark plugs, batteries, and electrical troubleshooting.
Derivation
From the Greek 'elektron' (amber, the original source of static electricity) and 'hodos' (a way or path). So an electrode is literally 'the way electricity travels' — the path it uses to get into or out of something.
Why Pilots Care
Electrode condition and gap directly affect spark strength, engine starting reliability, and smooth operation; worn or fouled electrodes can cause misfires or power loss.
Intuition Check
An electrode is not the electricity itself. It is the metal path or contact point that the electricity uses.
Example Sentence 1
The mechanic showed me the worn center electrode on the spark plug — that was why the engine had been running rough.
Example Sentence 2
A widened electrode gap can prevent the magneto from delivering a reliable spark at high altitude.