What is a "thermal" in aviation terminology?

A "thermal" refers to a rising column of warm air that provides lift, which is particularly important in gliding and soaring. As the sun heats the Earth's surface, certain areas warmth up more rapidly than others, resulting in pockets of air that become warmer than the surrounding air. This warmer air is less dense, causing it to rise. Gliders and soaring aircraft can take advantage of these thermals by circling in them, gaining altitude without the need for an engine. This principle is crucial for glider pilots looking to extend their flight duration and traverse long distances while relying purely on natural lift sources. Understanding thermals is essential for effective soaring techniques, as pilots must learn to identify and utilize these updrafts effectively.