GPO, the /ˌdʒiː piː ˈəʊ◂/ BrE AmE
1 . (the General Post Office) the former name of the organization that controls mail in the UK, now called the Royal Mail
2 . (the Government Printing Office) a US government organization that prints government documents, maps, books etc, which it gives to national libraries and government offices, and sells to the public at low cost