Don's bulbs rare light bulbs and lamps glossary of terms definition of: HID What is HID? HID refers to HIGH INTENSITY DISCHARGE. Metal Halide, High Pressure Sodium, Low Pressure Sodium and Mercury Vapor lamp types. references for this page: HIGH INTENSITY DISCHARGE, HID references to this page: /M, BALLAST, ELECTRIC DISCHARGE LAMP, ELECTRONIC BALLAST, HIGH PRESSURE SODIUM, LOW PRESSURE SODIUM, MERCURY VAPOR LAMP, PAR LAMP, REFLECTOR LAMP