Filament 2 : A thin wire or thread. In a thermionic valve, a wire that emits electrons when heated by an electric current. In an electric lamp, a wire that provides light by becoming incandescent when heated by the current
H. J. Porter (Chairman - Technical Committee), Dictionary of Fire Technology, The Institution of Fire Engineers, The Victory Press (Leicester) Ltd. 1979 UK. (Fr Tech - Brit) {81}