A heat spreader is a device that helps distribute heat evenly. It is used to keep things from getting too hot in one spot by spreading the heat out across a larger area. Full definition
The module is designed at a height that will fit most systems while still allowing for maximum cooling potential; the aluminum heat spreader. (thatvideogameblog.com)
Below are some pictures showing a simple press that can be used to make radiant floor heat spreader plates. (builditsolar.com)
With more than five times the thermal conductivity of copper, diamond is the ultimate heat spreader. (sciencedaily.com)