Thermal meaning : A column of rising air in the lower atmosphere created by uneven heating of Earth's surface. (stone) To create a rough finish on stone by treating it with a high-temperature blow-torch. (gliding, often in the present participle) To fly an unpowered aircraft in a (thermal) column of rising air. Pertaining to heat or temperature. (fabric) Providing efficient insulation so as to keep the body warm. Caused or brought about by heat. (stone) Having a rough finish by treatment with a blow-torch.