Short answers, pulled from the story.
It refers to a film that is unprofitable or considered highly unsuccessful during its theatrical run, especially a major studio release that was highly anticipated and expensive but still failed. The combined costs of production, marketing, and distribution exceed the revenue the film brings in.
The phrase originally described a film that exploded at the box office in a good way, meaning it was a hit. The United Kingdom kept using it with that positive meaning into the 1970s.
United Passions, a 2015 docudrama funded mostly by FIFA, reached American theaters just as FIFA's leaders were under investigation for fraud and corruption. It grossed only $918 at the US box office in its opening weekend.
Sahara's budget ballooned to $281.2 million for production, distribution, and other expenses. It earned $119 million in theaters and $202.9 million overall, leaving a net loss of $78.3 million.
Vertigo, Blade Runner, The Wizard of Oz, It's a Wonderful Life, Citizen Kane, The Shawshank Redemption, Showgirls, Fight Club, The Thing, and Scott Pilgrim vs. the World all lost money on initial release. Each later became a cult favorite.
Mars Needs Moms, released in 2011 as the final film from ImageMovers Digital, lost nearly $140 million when Disney absorbed the company's stake into ImageMovers. That loss makes it the largest box-office bomb ever recorded in nominal dollar terms.