To stay overnight somewhere; sleeping and lodging temporarily at a place, such as staying at a friend's house or lodging while away from home.
出張で二晩だけ会社の近くに寝泊まりした。
On a business trip I stayed overnight near the office for just two nights.
大学時代はサークルの合宿でよく寝泊まりしたものだ。
In university days I often stayed overnight during club camps.
親戚の家に寝泊まりする予定なので、荷物は少なめにした。
Since I plan to stay at a relative's house, I packed light.