headlight       
noun [ C usually plural ] uk/ˈhed.laɪt/ us/ˈhed.laɪt/ (UK also headlamp)
 (车辆的)头灯,前灯
a large, powerful light at the front of a vehicle, usually one of two
  I could see a car's headlights coming towards me. 我看见一辆车的前灯离我越来越近。 
 It was foggy, and all the cars had their headlights on. 天气雾蒙蒙的,所有的车都开着前灯。 
 to dip your headlights (= make them shine downwards) 把前灯调成近光 
 Compare: sidelight
 Idiom   
be like a deer/rabbit caught in the headlightsidiom  吓傻了,惊呆了
to be so frightened or surprised that you cannot move or think
  Each time they asked him a question he was like a deer caught in the headlights. 每次他们问他问题时,他都一副吓傻了的样子。