Definition
An electric lamp that produces light by passing a high-current electrical arc between two electrodes, either through a gas or in open air. The intense heat of the arc causes the gas or electrode material to glow with very bright light.
Plain English
A lamp that makes light by jumping electricity across a small gap between two metal points. The spark is so hot it glows brilliantly.
Context Anchor
Seen in aircraft electrical-system or lighting descriptions, especially for older high-intensity landing, search, or inspection lights.
Derivation
From the Latin arcus, meaning bow or curved shape. The electrical discharge between two electrodes forms a curved, bow-like band of glowing gas, which is why it is called an arc.
Why Pilots Care
Arc lamps can produce very bright light, but they can also involve high heat and electrical hazards, so pilots should treat them as equipment to be handled and serviced carefully.
Intuition Check
Arc does not mean a curved flight path here. It means a bright electrical discharge across a gap.
Example Sentence 1
The aircraft's powerful searchlight uses an arc lamp to produce a bright, focused beam visible from a great distance.
Example Sentence 2
Maintenance replaced the worn electrodes in the arc lamp before the next flight.