National Oceanographic Association
National Officers Association (EA)
National Onion Association (EA)
National Opera Association (EA)
National Optical Association - Later, NAOO
National Optometric Association (EA)
National Optometry Association (EA)
National Orchestral Association (EA)
National Outboard Association - Defunct (EA)
National Outdoorsmen's Association - Defunct (EA)
NATO Oil Authority (NATG)
Natural Optical Activity
Natural Orange Aroma
Nature of Action - Military (AFM)
Nearest Onshore Area (EEVL)
Nebraska Optometric Association (EARSL)
Net on Air (SAUS)
Network-Oriented Analysis and Transformation Unit - Computer science (MHDB)
New London, CT - Location identifier - FAA (FAAL)
New Obligational Authority
Noah's Lark Inc., Shawnee, OK - Manufacturer code for watercraft hull identification number (USCG)
Non-Operational Aircraft (SAUS)
Norontair - Canada - ICAO designator (FAAC)
Northwest Orient Airlines, Inc.
Notice of Arrival (EEVL)
Notice of Availability (MCD)
Not Operationally Assigned
Not Otherwise Authorized
NSWC Office Automation (SAUS)
Nueva Organizacion Antiterrorista - New Anti-Terrorist Organization - Guatemala (PD)
University of North Carolina, Chapel Hill Library School, Chapel Hill, NC - OCLC symbol (OCLC)
Woun Meu - Language code (ETLW)