Definition
The system of tubes or passages in a reciprocating engine that carries the fuel-air mixture (or air alone, in fuel-injected engines) from the carburetor or throttle body to the intake ports of each cylinder.
Plain English
The set of pipes that delivers air, or air mixed with fuel, from the engine's intake into each cylinder so it can be burned to produce power.
Context Anchor
You will see this term in piston-engine discussions, especially when learning about engine operation, fuel-air mixture, carburetor icing, and manifold pressure.
Derivation
From Latin 'inducere,' meaning 'to lead in,' and 'manifold,' an old English word meaning 'many' or 'having many parts.' Together it describes a single passage that branches out to lead air into many cylinders.
Why Pilots Care
An induction manifold leak or blockage causes uneven mixture distribution, leading to rough running, power loss, or engine damage.
Intuition Check
Do not confuse the induction manifold with the exhaust manifold. The induction manifold carries air, or air and fuel, into the engine; the exhaust manifold carries burned gases out.
Example Sentence 1
When carburetor ice forms in the induction manifold, airflow to the cylinders drops and engine power decreases.
Example Sentence 2
A restriction in the induction manifold reduced airflow to the rear cylinders and caused a noticeable drop in engine performance.