From Longman Dictionary of Contemporary Englishelectromagnetice·lec·tro·mag·net·ic /ɪˌlektrəʊmæɡˈnetɪk◂ $ -troʊ-/ adjective technical relating to both electricity and magnetism, or having both electrical and magnetic qualities electromagnetic wavesthe electromagnetic spectrum (=different waves of energy, including light, heat, radio waves, and X-rays)