taillight
/ˈteɪlˌlaɪt/
noun
- A red light at the back of a vehicle that turns on when the headlights are on and gets brighter when the brakes are applied, warning other drivers.
- The car in front of us had a taillight out, making it hard to see in the fog.
- She checked her taillights before the long road trip to make sure they were working.
- I noticed one of my taillights was broken, so I replaced it before driving at night.