Collins COBUILD Advanced Learner's English Dictionary - thermal

(thermals) 1. Thermal means relating to or caused by heat or by changes in temperature. ...thermal power stations. ADJ: ADJ n 2. Thermal streams or baths contain water which is naturally hot or warm. Volcanic activity has created thermal springs and boiling mud pools. ADJ: ADJ n 3. Thermal clothes are specially designed to keep you warm in cold weather. My feet were like blocks of ice despite the thermal socks... ADJ: ADJ n • Thermals are thermal clothes. Have you got your thermals on? N-PLURAL 4. A thermal is a movement of rising warm air. Birds use thermals to lift them through the air. N-COUNT