sorting office
noun1
A building in which mail is collected together, then sorted prior to delivery.
- The town has a long association with T.P.O. [travelling post office] working, the stock and operation of which has changed little over the years, but in 1961 new postal vans were introduced on the "York Mail" and a conveyor belt from platform 7 to the sorting office is to be installed to speed traffic.1963 January, Jeffrey P. Burke, “Railway crossroads of the north-west: Shrewsbury”, in Modern Railways, page 51: