Altimeter

An instrument that indicates flight altitude by sensing pressure changes and displaying altitude in feet or meters.

Helicopter Flying Handbook, p. G-1

Also defined in 1 more source

A flight instrument that indicates altitude by sensing pressure changes.

Pilot's Handbook of Aeronautical Knowledge, p. G-3

Taught in AF-H Quick reference, GEN-J Procedures, AF-I Quick reference, AF-H Concepts, GEN-J Quick reference.