Plain English Meaning
The shaped cover that wraps around the engine. It keeps the engine tidy, lets cooling air flow through it, and shields it from rain, dirt, and damage.
Full Definition
The removable metal or composite housing that encloses an aircraft engine. The cowling streamlines the engine compartment, directs cooling airflow over the cylinders, and protects engine components from weather and debris.
Context Anchor
You encounter the cowling during preflight inspection, engine checks, and discussions of engine cooling.
Derivation
From the old word 'cowl,' meaning a hood or covering — originally the hood worn by monks. The cowling 'hoods' the engine in much the same way.
Why Pilots Care
A properly fitted cowling maintains engine within safe limits and cuts ; loose or damaged can cause overheating or loss.