Headlight (noun)

1. A powerful light mounted on the front of a vehicle that is used to illuminate the road ahead.
2. A light that is mounted on the front of a bicycle or motorcycle and that is used to help the rider see and to be seen by others.

Origin:

Headlight (n.) 1875, from head (n.) + light (n.).

Examples:

1. He turned on the headlight of the car.
2. She was riding her bike with a headlight.
3. The headlight of the truck was on.
4. He was replacing the headlight of his car.
5. She was checking the headlight of her motorcycle.