also La La land; la-la land
1.
People sometimes refer to Los Angeles, in particular the Hollywood district of Los Angeles, as ~. (HUMOROUS, INFORMAL)
...her position as ~’s premiere hairdresser.
N-UNCOUNT
2.
People sometimes use ~ to mean an imaginary place. (INFORMAL)
For much of the time he was in hospital, he was under sedation. ‘I was in La La Land,’ he said.
= cloud-cuckoo land
N-UNCOUNT