Other forms: sleepovers
A sleepover is a night spent at a friend's house. Have a sleepover, invited to a sleepover, a birthday sleepover.
It is a children's institution and one of the first nights most people spend away from their own family, which is why it matters more than it looks. The word is one word as a noun and two as a verb — to sleep over. It is chiefly American in origin.
1nounsleepoverA night spent at a friend's house.
“My daughter is having a sleepover with three friends on Friday.”
sleepover is a stay.
Sleep plus over, from the phrase to sleep over. The noun is American and dates from the mid twentieth century.
From sleep + over.
Etymology from Wiktionary, CC BY-SA