#altimeter
- Altigraph — An automatic recording instrument (barographic altimeter) used in aviation and meteorology to continuously measure and graphically trace on a chart the altitude variations of an aircraft or a weather balloon based on changes in atmospheric pressure.
- Altimeter — A flight instrument or portable device used in aviation, mountaineering, and surveying to measure and display the altitude of a point or an aircraft relative to a predetermined reference level (usually sea level or ground level), operating on barometric, radio, or laser principles.