Here are some examples:
* Thermometer: An instrument used to measure temperature.
* Thermos: A container designed to keep things hot or cold.
* Thermostat: A device that regulates temperature.
* Thermodynamics: The study of heat and its relation to other forms of energy.
* Thermal: Relating to heat.
It's important to note that the prefix "ther" is sometimes used in other contexts, but the meaning of heat is the most common.