The title comes from the children's rhyme that the main character, Randle Patrick McMurphy, sings in the novel:
> "I'm a sailor, I'm a sailor,
> I'm a sailor, I'm a sailor.
> I've a girl in every port,
> I've a girl in every port.
> I've a girl in every port,
> And I'm a sailor, I'm a sailor.
> I've a girl in every port,
> And I'm a sailor, I'm a sailor.
> I'm a sailor, I'm a sailor,
> I'm a sailor, I'm a sailor.
> One flew over the cuckoo's nest.
> One flew over the cuckoo's nest."
The rhyme itself has no clear meaning and is likely nonsensical, which reflects the chaotic and absurd nature of the story.
In the context of the novel, the phrase "one flew over the cuckoo's nest" is interpreted as a metaphor for escaping the confines of the mental institution and regaining one's freedom. The cuckoo's nest represents the stifling environment of the ward, and McMurphy's defiance and rebellion against the system are symbolic of the attempt to fly over it.