Definition
A cockpit instrument that combines a rotating magnetic compass card with one or two pointers (needles) that always point toward a selected navigation station, such as a VOR or NDB. The pilot reads the bearing to the station directly off the compass card under the tip of the needle.
Plain English
An instrument that shows you which direction a navigation station is from the airplane, using a needle on a compass face that turns with the aircraft.
Context Anchor
Seen on instrument panels and in instrument procedure discussions when checking position or comparing navigation indications against another system.
Derivation
Radio Magnetic Indicator -- 'radio' because the needle is driven by a radio navigation receiver, 'magnetic' because the underlying compass card is referenced to magnetic north, and 'indicator' because it displays bearing information visually.
Why Pilots Care
Gives immediate bearing information without mental math, reducing workload and improving accuracy when tracking to or from navigation aids in instrument conditions.
Intuition Check
Do not assume an RMI shows whether you are exactly on a selected course. It points toward a radio navigation station; it does not by itself show left-or-right course error.
Example Sentence 1
During the RNAV accuracy check, the pilot compared the bearing shown on the RMI to the expected bearing for the VOR.
Example Sentence 2
During the RNAV accuracy check the RMI needle aligned with the expected radial, verifying position.