"To spend the night" means to stay overnight at a specific place, usually in another person's house or at a hotel. It refers to sleeping and being in that location throughout the night before leaving the next morning. Full definition
If you are planning on spending your night in with your girlfriends, I've got you covered. (beautywithlily.com)
Join in an optional tour of the city or have the afternoon at leisure before spending the night at your hotel. (rovos.com)
After spending a night with her boyfriend, a naive teenager learns that the consequences of her actions are more dangerous than she realized. (tubitv.com)