The crossword solution for the term 'Glow with Heat' is INCANDESCENT, which has 12 letters. Incandescence is a phenomenon of light emission from a heated object, such as a light bulb or a star. It is caused by the thermal energy of the object being converted into electromagnetic radiation, which is visible to the human eye. Incandescence is the most common form of visible light emission and is used in many everyday applications, such as lighting and heating.