Definition
An instrument used to measure pressure, typically by balancing the pressure being measured against a column of liquid (such as mercury or water) or against a calibrated mechanical element. The height of the liquid column, or the deflection of the mechanical element, indicates the pressure.
Plain English
A device that measures how much pressure something has, often by showing how high it pushes a column of liquid up a tube.
Context Anchor
Seen in aircraft maintenance and instrument-system checks, especially when measuring small pressure changes or checking for leaks.
Derivation
From the Greek 'manos' meaning 'thin' or 'rare' (as in rarefied gas) and 'metron' meaning 'measure.' Originally a device for measuring the rarity or pressure of gases. Knowing this helps explain why the term applies broadly to any pressure-measuring instrument, not just one specific type.
Why Pilots Care
Accurate pressure readings are essential for verifying fuel delivery and engine performance during maintenance.
Analogy
A simple manometer works like a clear tube partly filled with liquid: more pressure on one side pushes the liquid farther, and the amount it moves shows the pressure.
Intuition Check
Do not think of a manometer as a weather instrument only. In aviation, it is a pressure-measuring tool used wherever accurate gas or liquid pressure matters.
Example Sentence 1
The technician connected a manometer to the static system to verify the altimeter was reading correctly.
Example Sentence 2
A manometer confirmed the manifold pressure was within limits after the engine overhaul.