retroreflector
/ˌrɛtroʊrɪˈflɛktər/
noun
- A device or surface that reflects light back toward its source, often used on roads, vehicles, or clothing for safety.
- Road signs use retroreflectors so drivers can see them in the dark.
- The safety vest was covered in retroreflectors to help construction workers stay visible.
- The bicycle had a small retroreflector on the back to make it visible at night.