Plain English Meaning
The hand on the altimeter dial that points to numbers showing how high the airplane is. Like the hands on a clock, but instead of telling time, it tells altitude.
Full Definition
A pointer on the face of the altimeter that rotates against a graduated scale to display the aircraft's altitude. Most sensitive altimeters use multiple needles: a long needle indicating hundreds of feet and a shorter needle indicating thousands of feet, with a third pointer or window often showing tens of thousands of feet.
Context Anchor
Seen during the instrument scan, especially when holding altitude in straight-and-level flight.