Eclipse (A Piece for Assorted Lunatics)" was the working title.

Before they settled on The Dark Side of the Moon, Pink Floyd called it “Eclipse (A Piece for Assorted Lunatics)”. The band considered a few names, including a simple “Eclipse,” but eventually dropped it because another band had an album called Eclipse. They also wanted something that suggested the album’s themes of madness and pressure, so “The Dark Side of the Moon” stuck. Fun fact: the final track on the album is still called “Eclipse.”