From Longman Dictionary of Contemporary Englishsorting officeˈsorting ˌoffice noun [countable] British English TCMBBOa place where letters and packages are put into groups according to where they have to be delivered
Examples from the Corpus
sorting office• The items were intercepted in Haverhill by a sorting office worker.• The others are also understood to have passed through the main sorting office in Crown Street.• Five similar devices were found in mail at the building's sorting office and defused by the Army.• Lance Rees was set on as he passed the sorting office in Withernsea, Humberside, on his way to school.• Graham smiled and crossed the road to the sorting office, smelling its new coat of paint.From Longman Business Dictionarysorting officeˈsorting ˌoffice [countable] British English a place where letters and packages that have been collected from post boxes are put into groups according to where they have to be delivered → office 