1. 热的;由热引起的;温度变化引起的
    Thermal means relating to or caused by heat or by changes in temperature.

    e.g. ...thermal power stations.
           热电厂
    e.g. ...financial assistance with repair, thermal insulation and improvements to homes through Government grants.
           政府拨款供修缮、隔热和房屋改造之用的经济援助

2. (小溪、浴水)天然温热的
    Thermal streams or baths contain water which is naturally hot or warm.

    e.g. Volcanic activity has created thermal springs and boiling mud pools.
           火山活动产生了温泉和沸腾的泥浆池。

3. (衣服)保暖的，御寒的
    Thermal clothes are specially designed to keep you warm in cold weather.

    e.g. My feet were like blocks of ice despite the thermal socks...
           虽然穿了保暖袜子，我的双脚还是像冰块一样。
    e.g. I put on my thermal leggings, long socks and the rest of my clothes.
           我穿上保暖紧身裤、长袜和其他衣服。

4. 上升热气流
    A thermal is a movement of rising warm air.

    e.g. Birds use thermals to lift them through the air.
           鸟类利用上升热气流升入空中。