Plain English Meaning

A small adjustment that lets you take your hand off the yoke without the nose pitching up or down. You set it once for the pitch you want, and the airplane stays there on its own.

Full Definition

A pilot-adjustable system that relieves the control pressure required to hold the elevator in a desired position, allowing the airplane to maintain a chosen pitch attitude or airspeed without continuous force on the control yoke or stick. It is typically operated by a trim wheel, crank, or electric switch in the cockpit and works by deflecting a small on the elevator (or by repositioning a movable ) so the itself holds the elevator where wants it.