The title of the book is a line from a nursery rhyme:
Vintery, mintery, cutery, corn, Apple seed and apple thorn, Wire, briar, limber lock Three geese in a flock One flew East One flew West And one flew over the cuckoo's nest
Chief Bromden's grandmother sang a version of this song to him when he was a child, a fact revealed in the story when the Chief received yet another ECT treatment after he assisted McMurphy with defending George, a patient being abused by the ward's aides.