altimeter

/ælˈtɪmətər/

Other forms: altimeters

An altimeter measures how far above ground something is. You wouldn't want to fly a plane without an altimeter!

The two halves of altimeter should give you a clue to its meaning: altitude is height above ground, and meters are used to measure distance. An altimeter measures altitude. This is an extremely important device in the field of aviation. When flying an airplane, pilots needs to know exactly what their altitude is: the altimeter tells them. Pilots flying helicopters, blimps, and other flying vehicles use altimeters too. A plane without a working altimeter isn't safe to fly.

Definitions of altimeter

1. noun

   an instrument that measures the height above ground; used in navigation
   types:

   hypsometer

   an altimeter that uses the boiling point of water to determine land elevation

   type of:

   measuring device, measuring instrument, measuring system

   instrument that shows the extent or amount or quantity or degree of something