Definition
An ignition timing setting in which the spark occurs in the cylinder before the piston reaches top dead center on its compression stroke. The amount of advance is measured in degrees of crankshaft rotation before top dead center.
Plain English
The spark plug fires a little early -- before the piston has finished pushing the fuel-air mixture up to the top of the cylinder. This gives the burning fuel enough time to develop full pressure right when the piston starts heading back down.
Context Anchor
Seen in piston-engine maintenance, magneto timing checks, engine troubleshooting, and discussions of abnormal combustion or high engine temperatures.
Derivation
Advanced' here comes from the Latin 'ab ante' meaning 'from before.' In timing, it means the event happens earlier than a reference point -- in this case, earlier than top dead center.
Why Pilots Care
Correct advanced timing improves power and efficiency; excessive advance risks detonation and engine damage.
Analogy
It is like pushing a swing before it reaches the right spot. The push may be strong, but because it comes too early, it works against the motion instead of helping it.
Intuition Check
Advanced does not mean more modern or better here. It means the ignition spark is happening earlier than the correct timing setting.
Example Sentence 1
The mechanic checked that the magneto was set to the correct advanced timing specified in the engine manual.
Example Sentence 2
During the preflight magneto check, confirm both magnetos fire at the specified advanced position.