stay at somebody's flat BrE
stay at somebody's apartment AmE

Having nowhere to go, she stays at Thomas' apartment with his mother and siblings.

Her father, who is staying at a friend's apartment, "calls me every night," she said.

Often staying at her apartment when he was in town rather than his own.

Oliver has no one to turn to but Philip, who invites him to stay at his apartment.

She had reportedly also stayed at Grover's apartment for a few days.

One night, he stayed at a friend's apartment after a party.

I'm checking out of here today and going to stay at a friend's apartment.

It just means that unless we can truly compromise, I'll be better off staying at my apartment.

I figured you could stay at my apartment rather than a hotel.

She let Manson stay at her apartment and, after a period of weeks, the two began sleeping together.