Plain English Meaning
A protective wall between the engine and the cabin that is built to resist fire and heat, keeping any engine fire away from the people inside the aircraft.
Full Definition
A structural wall, typically called a firewall, built from heat-resistant material that separates the engine compartment from the rest of the aircraft. It is designed to contain an engine fire long enough to allow the pilot to land safely, and to shield the cabin from heat, flame, and engine fluids.
Context Anchor
Seen in aircraft structure discussions, especially where the engine area is separated from the fuselage or cabin.
Derivation
Fireproof comes from 'fire' plus 'proof' meaning 'able to resist.' Partition comes from the Latin 'partire' meaning 'to divide.' Together: a dividing wall that resists fire.