Altimeter (noun)

An instrument that measures the altitude of an aircraft or other object above a fixed level, such as sea level.

Origin:

Late 19th century, from latin altus (high) + -meter (measure).

Examples:

1. The pilot checked the altimeter before take-off to ensure they were at the correct altitude.
2. The altimeter showed that the aircraft was at an altitude of 30,000 feet.
3. Altimeter is an essential instrument for aircraft navigation and safety.
4. The altimeter is used to measure the height above sea level.
5. The altitude of the mountain was measured using an altimeter.