Incandescent lamp that generates light by passing an electric current through a thin filament wire (usually of wolfram) until it is extremely hot. The lamps are often filled by a halogen gas such as iodine and bromine that allow filaments to work at higher temperatures and higher efficiencies.
See: quartz–iodine lamp
PAC, 2007, 79, 293. 'Glossary of terms used in photochemistry, 3rd edition (IUPAC Recommendations 2006)' on page 440 (https://doi.org/10.1351/pac200779030293)