Plain English Meaning

The smooth, rounded housing around an aircraft engine. It covers the engine and helps the air flow cleanly past it.

Full Definition

A streamlined enclosure on an aircraft that houses an engine, and sometimes other components such as fuel, landing gear, or systems equipment. The nacelle is shaped to reduce drag and is typically mounted on a wing, on the fuselage, or at the tail.

Context Anchor

Seen in aircraft systems discussions, especially when describing engine anti-ice protection around the engine housing and front opening.

Derivation

From the French nacelle, meaning 'small boat' or 'cradle,' which itself comes from the Latin navicella, a diminutive of navis ('ship'). The aviation use carries that same idea of a shaped that cradles something inside it -- in this case, the engine.