Longman Dictionary of Contemporary English
rearview mirror
noun
EXAMPLES FROM CORPUS
▪ Happiness is your competitors disappearing in your rearview mirror.
▪ I looked at myself in the rearview mirror.
▪ In the rearview mirror, the eyes were searching for and not finding Wally: they were startlingly large.
▪ Jen said, eyeing them in the rearview mirror.
▪ Not cocky enough not to watch my speed, though, nor to keep looking in the rearview mirror.
▪ The large eyes in the rearview mirror looked away.
▪ Tired eyes flashing in the rearview mirror, childish enthusiasm bubbling over.
Wiktionary
rearview mirror
n. (alternative form of rear-view mirror English)
WordNet
rearview mirror
n. car mirror that reflects the view out of the rear window