sleepover
From Longman Dictionary of Contemporary Englishsleepoversleep‧o‧ver /ˈsliːpəʊvə $ -oʊvər/ noun [countable] PARTYa party for children in which they stay the night at someone’s houseExamples from the Corpussleepover• Probably never even spent the night out except at a sleepover, huh?• I decided that it called for a spooky sleepover, so I invited my mates over one evening.• The White House is more than the ultimate sleepover.