Plain English Meaning
Someone trained and licensed to fly an aircraft that has no engine, using air currents to stay aloft.
Full Definition
A pilot certificated to operate a glider, which is a heavier-than-air aircraft that sustains flight without an engine by using rising air currents and energy management techniques rather than powered thrust.
Context Anchor
Seen when FAA material compares powered-airplane flying with glider flying, especially in discussions of stalls, speed control, and landing decisions.