A public announcement is when information is shared with a large group of people to make them aware of something important or to make it officially known to everyone. Full definition
This may have been the first public announcement of the event. (si.com)
All political parties love to make public announcements in support of infrastructure spending, and why not? (3dpolicy.ca)
Public announcements in noisy places — such as railway stations, airports, or sports venues — could become quieter and clearer in future, thanks to new research. (sciencedaily.com)