Say “Good night” to say “goodbye” – when you are leaving to go home. Family members also say “good night” when they are going to bed. “Good night, Janet.

What time do you say good night?

"Good evening" is something that can be used from roughly 5 PM on. "Good night" can also be said from 5 PM on, but usually means one of two things: "goodbye (for the rest of the day, because we are leaving work, the bar, etc.)"

Which is correct goodnight or good night?

To recap, if you're going to write a farewell to someone at night or address a farewell to someone in writing, use the two-word variant: good night. But if you're talking about the noun or noun adjective, use the one-word form, goodnight.