diathermic

Diathermic is an adjective used in physics, engineering, and medicine to describe the ability of a material, barrier, or process to transmit heat. In thermodynamics, a diathermic substance readily conducts heat or permits thermal radiation to pass, in contrast with adiathermic (insulating) materials which resist heat transfer. A diathermic wall or window pane is designed to allow heat transfer across it, either by conduction or by radiative exchange.

In materials science, diathermic properties are important for heat exchangers, thermal insulation design, and safety considerations, where the goal is to manage heat flow between adjacent spaces or components. The term can also apply to the transparency of a medium to thermal radiation, as in diathermic media that permit infrared or other radiation to traverse with minimal absorption.

In medical contexts, diathermy refers to the therapeutic use of high-frequency electric currents to generate heat within body tissues. Shortwave and microwave diathermy are practiced modalities intended to relieve pain, improve tissue extensibility, or treat muscle spasm; they require clinical expertise because improper use can cause burns or interference with implanted devices.

Etymology: diathermic derives from Greek dia through and thermē heat, reflecting the sense of heat passing through a material or barrier.

Diathermic is related to diathermy, diathermic barriers, and adiathermic insulators, and is used in contrast with terms describing poor heat transfer.