Headlamps and Front Flasher Lamps

Discovery 3 Headlamps and Front Indicators
A Xenon headlight is when a vehicle will have an HID bulb used for the low beam and then a standard halogen bulb used for the high beam.
Bi-Xenon is when both the low and high beam are using the same HID bulb. When the low beam is being used a restrictor is used to shield part of the bulb so not to dazzle other drivers. When you engage the high beams the restrictor opens up and shines a light pattern typical of a high beam headlight.
Adaptive Bi-Xenons have aiming devices controlled by a steering angle sensor so the lights will corner with you.