What does altimeter mean?
An altimeter is an instrument that measures altitude — the height of an object above a given reference point, most commonly sea level. It is best known as essential equipment in aircraft cockpits, where pilots rely on it continuously to maintain safe vertical separation from terrain and other aircraft. Altimeters work in two principal ways: barometric models infer height from changes in atmospheric pressure, while radar (or radio) altimeters bounce signals off the ground to measure absolute clearance directly. Beyond aviation, compact altimeters appear in mountaineering watches, smartphones, and surveying instruments, helping hikers and climbers track their elevation gain. The word derives from the Latin 'altus', meaning high, combined with '-meter', from Greek 'metron', meaning measure — a fitting name for a device whose entire purpose is to quantify height. Though technical in register, the term is widely understood thanks to its prominence in aviation contexts.
nounAn instrument used to measure altitude, typically the height of an aircraft or other object above a fixed reference level such as sea level.
- An instrument, especially in aircraft, that measures altitude above a fixed level (usually sea level), typically using barometric pressure or radio waves.
"The pilot checked the altimeter as the plane climbed through ten thousand feet."
"Before beginning the descent, the co-pilot cross-checked the altimeter against the airfield's elevation."
"Hikers carrying a wristwatch with a built-in altimeter can track how much elevation they've gained on the trail."
Standard plural; used when referring to multiple instruments or devices across different aircraft or locations.
"Both aircraft were fitted with redundant altimeters for safety."
The word 'altimeter' comes from Latin 'altus' meaning high — the same root that gives us 'altitude', making it literally a 'high-measurer'.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of altimeter
The word 'altimeter' is formed from the Latin 'altus' (high) combined with the Greek-derived suffix '-meter' (measure), following the pattern of scientific measuring instruments such as the thermometer and speedometer. It emerged in English during the late nineteenth century alongside the development of scientific aviation and precision instrumentation. It shares its root with related terms like 'altitude' and 'altimetry', all tracing back to the same Latin source for height.
How altimeter is actually used
A technical term used chiefly in aviation, mountaineering, and meteorology; not part of everyday casual speech. Plural is standard.
Easily confused with altimeter
An odometer measures distance traveled by a vehicle, while an altimeter measures height above a reference level.