(in a post office) a locked compartment into which the mail of a box renter is put to be called for. Abbreviation: POB, P.O.B.
Origin of post-office box
An Americanism dating back to 1825–35
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
post office box
a private numbered place in a post office, in which letters received are kept until called for
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012