What is the meaning of Thermal?

Pertaining to heat or temperature.

Providing efficient insulation so as to keep the body warm.

Caused or brought about by heat.

Having a rough finish from treatment with a blowtorch.

A column of rising air in the lower atmosphere created by uneven heating of a planet's surface.

To create a rough finish on stone by treating it with a high-temperature blowtorch.

To fly an unpowered aircraft in a thermal (column of rising air).

thermal

thermal

Source: wiktionary.org