Entry 1 sense Webster, 1913 Thermomagnetism /(thẽr"mō̇*măg"nĕt*ĭz'm)/ · Ther·mo·mag·net·ism · IPA 01 n. Magnetism as affected or caused by the action of heat; the relation of heat to magnetism. 1. Magnetism as affected or caused by the action of heat; the relation of heat to magnetism.