Definition
The system of tubes or passages on a piston engine that carries the fuel-air mixture from the carburetor or fuel injection system to each cylinder's intake port. In a typical aircraft engine, the manifold splits a single source flow into separate runners, one for each cylinder, so that all cylinders receive a roughly equal charge on each intake stroke.
Plain English
The set of pipes that delivers the fuel and air mixture from the carburetor to each cylinder of the engine.
Context Anchor
Seen in engine power discussions, especially when using a manifold pressure gauge with an adjustable-pitch or constant-speed propeller.
Derivation
From Latin manus (hand) and folium (leaf), giving manifold the sense of "many branches from one source." That image fits perfectly here: one flow of fuel-air mixture branching out to feed several cylinders.
Why Pilots Care
Even distribution of the mixture keeps the engine running smoothly and producing consistent power; leaks or restrictions can cause roughness or power loss.
Analogy
Think of it like a hallway that branches into several rooms. Air enters the hallway, then the branches carry it to each cylinder.
Intuition Check
Do not think of the intake manifold as just the outside air opening or air scoop. It is the set of passages inside the engine area that carries air onward to the cylinders.
Example Sentence 1
After starting the engine, the pilot checked that the intake manifold was delivering an even mixture by watching for smooth idle on all cylinders.
Example Sentence 2
During climb the adjustable-pitch propeller increased engine load, requiring the intake manifold to deliver a richer mixture evenly to all cylinders.