Stop Press Meaning
(Britain, journalism) The event or news article important enough to delay or interrupt the print, or require a reprint, of a publication, particularly of a newspaper edition.
Example: 1989, Textual Introduction to The Anatomy of Melancholy, Robert Burton 
Three of the errata corrections had already been made as stop-press corrections [...]
2002, Russell Miller, Behind the Lines 
Faked Stop Press! announcements in newspapers. A valuable trick because it can always be claimed that the announcement was â€˜hushed upâ€™. It is also easy to fake the printing of the Stop Press.
2005, Mary Norway, The Sinn Fein Rebellion As I Saw It, 
Another lady thought she would drive a lesson home, so she said: â€œBut you said it was a â€˜Stop press,â€™ and you knew it was not.â€
â€œIt is, miss, but sure they hadnâ€™t time to print the â€˜stop pressâ€™ on it!!â€
(â€œStop pressâ€ is the latest news, usually printed on the back of the paper.)