Diathermal is a word that refers to the ability of materials to allow heat to pass through them. There are several synonyms for this word that can be used in scientific contexts, such as thermally conductive, thermally permeable, or thermally transparent. They all denote an object's ability to conduct heat or allow it to pass through unimpeded. Other synonyms include heat-transmitting, heat-conveying, and thermally diffusive. All of these words mean that a material can allow heat to pass through it, which can be useful in many applications, such as the construction or manufacturing of industrial equipment, thermal insulators, and even clothing.