Catch phrase from a Beatles tune that was a malapropism spoken by Ringo Starr and turned into a song by John Lennon. It also became the title for their film and album.
From the Wikipedia Entry:The song's title originated from something said by Ringo Starr, The Beatles' drummer. Starr described it this way in an interview with disc jockey Dave Hull in 1964: "We went to do a job, and we'd worked all day and we happened to work all night. I came up still thinking it was day I suppose, and I said, 'It's been a hard day... and I looked around and saw it was dark so I said, '...night!' So we came to 'A Hard Day's Night.'"
Starr's statement was the inspiration for the title of the movie, which in turn inspired the composition of the song. According to Lennon in a 1980 interview with Playboy magazine: "I was going home in the car and Dick Lester [director of the movie] suggested the title, 'Hard Day's Night' from something Ringo had said. I had used it in In His Own Write [a book Lennon was writing then], but it was an off-the-cuff remark by Ringo. You know, one of those malapropisms. A Ringo-ism, where he said it not to be funny... just said it. So Dick Lester said, 'We are going to use that title.'"