DS here from google search (sorry for cut and paste) .... cheers

Dipped beam (low beam, passing beam, meeting beam)
Dipped-beam (also called low, passing, or meeting beam) headlamps provide a light distribution to give adequate forward and lateral illumination without blinding other road users with excessive glare. This beam is specified for use whenever other vehicles are present ahead. The international ECE Regulations for headlamps specify a beam with a sharp, asymmetric cutoff preventing significant amounts of light from being cast into the eyes of drivers of preceding or oncoming cars.[3][4] Control of glare is less strict in the North American SAE beam standard contained in FMVSS / CMVSS 108.[5] ..........(see also fog light)