Publication 28 - Postal Addressing Standards > Appendix C > C2 Secondary Unit Designators
Description
Approved Abbreviation
Apartment
APT
Basement
BSMT**
Blank, unable to determine*
Building
BLDG
Department
DEPT
Floor
FL
Front
FRNT**
Hanger
HNGR
Key
KEY
Lobby
LBBY**
Lot
LOT
Lower
LOWR**
Office
OFC**
Penthouse
PH**
Pier
PIER
Rear
REAR**
Room
RM
Side
SIDE**
Slip
SLIP
Space
SPC
Stop
STOP
Suite
STE
Trailer
TRLR
Unit
UNIT
Upper
UPPR**
* Requires the pound sign (#) to be used on the mailpiece.
** Does not require a Secondary RANGE to follow.