You know what it looks like… but what is it called?
TAKE THE QUIZ“on the back”
The following 4 entries include the term on the back.
a pat on the back
noun phrase: a show of praise or approval
a slap on the back
noun phrase: the act of slapping someone's back usually to express praise or approval
on the back burner
idiom: in the position of something that will not receive immediate attention and action
on the back of
idiom: because of or on the strength of (something)