reflector
nounUK /rɪˈflektə/
US /rɪˈflektər/
A reflector is a thing that bounces light back.
The bike has a red reflector on the back so cars can see it at night.
OTHER MEANINGS
2. A small piece of glass or plastic on a road or vehicle that shines back when light hits it.
The road markers have reflectors that glow when headlights shine on them.
3. A telescope that uses a curved mirror to gather light.
He looked at the moon through his new reflector telescope.
4. A person or thing that shows or expresses something.
The newspaper is a reflector of public opinion.