Definition
The system of pipes or passages that distributes the air-fuel mixture (or, in fuel-injected engines, the air alone) from the carburetor or throttle body to each cylinder's intake port in a reciprocating aircraft engine. In a turbocharged engine, the manifold also receives compressed air from the turbocharger and is the location where manifold pressure is measured.
Plain English
The set of pipes that delivers air into the engine's cylinders. It's the plumbing that splits one airflow path into one branch for each cylinder.
Context Anchor
You will see this term in discussions of piston engine induction systems, turbocharging, and manifold pressure.
Derivation
From Latin 'inducere' (to lead in) and 'manifold' meaning 'many' — literally a fitting that leads air in and splits it into many branches, one per cylinder.
Why Pilots Care
Ensures even distribution of pressurized air so every cylinder produces consistent power and avoids detonation or power loss from uneven mixture.
Intuition Check
Do not confuse the induction air manifold with the exhaust manifold. The induction air manifold brings air into the engine; the exhaust manifold carries burned gases out.
Example Sentence 1
After the turbocharger compresses the outside air, that air flows into the induction air manifold and on to the cylinders.
Example Sentence 2
A cracked induction air manifold caused a noticeable drop in manifold pressure during the climb.