What's Up With the Title?
Here's a shocker: One Flew Over the Cuckoo's Nest takes its title from a novel by Ken Kesey that went by the same name and was published in 1962.
Which begs the question: where'd Kesey get the idea in the first place?
Kesey took the title from an old rhyme that talks about three geese in a flock. According to the poem, "One flew east, one flew west, and one flew over the cuckoo's nest." We can tell that this last line is significant because the "cuckoo's nest" in this case must be the mental hospital, as mentally ill people have been associated with the cuckoo bird for hundreds of years.
The idea that "one flew over" the cuckoo's nest refers to the fact that one person in this movie is going to escape from the mental hospital. For most of the movie, you would assume that it's going to be McMurphy who escapes. But in the end, we realize that it's actually Chief Bromden who gets away. In terms of symbolism, it doesn't really matter who escapes. The important thing is that freedom isn't completely dead—it's there for those who are brave enough to take it. There truly is a reason to defend your pride and self-esteem, no matter how much the world tries to beat you down. And in this sense, we're all trying to be the one who flies over the cuckoo's nest.