Definition
A portable device carried in the aircraft that discharges a chemical agent (commonly Halon or a Halon replacement) to suppress a fire by interrupting combustion, smothering the flames, or cooling the fuel source. Aircraft fire extinguishers are sized for cabin and cockpit use and are intended for small, contained fires such as electrical, upholstery, or minor cabin fires.
Plain English
A handheld bottle in the cockpit that sprays a fire-killing chemical when you squeeze the trigger. It's there to put out small fires inside the airplane.
Context Anchor
You encounter this term in aircraft equipment checks and in emergency procedures for smoke or fire in the cabin.
Derivation
From Latin extinguere, 'to put out' or 'quench.' The word literally describes a tool that puts out fire. Knowing the root reinforces that its only job is to stop a fire that has already started -- it is not a preventive device.
Why Pilots Care
Provides the first and often only means to contain a cabin fire before it forces an emergency descent or evacuation.
Intuition Check
Do not assume a fire extinguisher makes every fire safe to fight. It is for small, reachable fires; if the fire, smoke, or fumes make the cabin unsafe, landing and getting people out become the priority.
Example Sentence 1
After noticing smoke from behind the instrument panel, the pilot pulled the circuit breaker and used the cockpit fire extinguisher to suppress the flames.
Example Sentence 2
During the preflight inspection the crew confirmed the fire extinguisher gauge showed full pressure and the mounting bracket was secure.