A headlamp is a lamp attached to the front of a vehicle to illuminate the road ahead. Headlamps are also often called headlights, but in the most precise usage, headlamp is the term for the device itself and headlight is the term for the beam of light produced and distributed by the device.
Low beam
Low beam (dipped beam, passing beam, meeting beam) headlamps provide a distribution of light designed to provide forward and lateral illumination, with limits on light directed towards the eyes of other road users to control glare. This beam is intended for use whenever other vehicles are present ahead, whether oncoming or being overtaken.
High beam
High beam (main beam, driving beam, full beam) headlamps provide a bright, center-weighted distribution of light with no particular control of light directed towards other road users’ eyes. As such, they are only suitable for use when alone on the road, as the glare they produce will dazzle other drivers.
Left- and right-hand drive
Most low-beam headlamps are specifically designed for use on only one side of the road. Headlamps for use in left-traffic countries have low-beam headlamps that “dip to the left”; the light is distributed with a downward/leftward bias to show the driver the road and signs ahead without blinding oncoming traffic. Headlamps for right-traffic countries have low beams that “dip to the right”, with most of their light directed downward/rightward.
