Plain English Meaning

A marked metal stick that you pull out of the engine to check how much oil is inside. The wet line on the stick shows the oil level against the markings.

Full Definition

A long, thin metal rod inserted into the engine's oil sump through a sealed tube, used to measure the quantity of engine oil. The lower end is marked with graduations (typically in U.S. quarts) showing the current oil level when the stick is withdrawn, wiped, reinserted, and read.

Context Anchor

Used during the preflight inspection when checking engine oil quantity before starting the engine.

Derivation

From 'dip' (to lower briefly into a liquid) and 'stick' (a thin rod). The name describes the action: you dip the stick into the oil to measure it.

Why Pilots Care

Confirms adequate lubrication before to prevent engine damage or failure.