1. stop press - Noun
2. stop press - Verb
stop press
(UK, 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.
(UK) Used to announce an event or news article important enough to delay or interrupt the print, or require a reprint, of publication, particularly of a newspaper edition.
(idiomatic, UK) Used to grab attention, implying importance, news-worthiness, etc.
Source: en.wiktionary.org