The red lights at the back of a car that turn on when the car is braking or driving in the dark.
Taillights help other drivers see the car and know when it's stopping.
Examples:
The car's taillights are red.
I can see the taillights of the car in front of us.
When it gets dark, the taillights turn on.
The taillights look like two red eyes in the dark.
The taillights were so bright, I could see them from far away.
I like to pretend the taillights are little red monsters following us.