NCA National Command Authority
NCO noncommissioned officer
NCO Network-Centric operations
NCW Network-Centric Warfare; Netcentric Warfare
ND Navy Department
NDO nuclear deterrence operations
NDU National Defense University
nec necessary
NECC Navy Expeditionary Combat Command
NETCOM Army Network Enterprise Technology Command
NETF naval expeditionary task force
NG National Guard
NGB National Guard Bureau
NIC network interface controller
NIIN national item identification number
NIR near-infrared
NMAWC Naval Mine and Anti-Submarine Warfare Command
NMD national missile defense
NOD night optical/observation device
noncom noncommissioned officer
NORAD North American Aerospace Defense
NOTAR no tail rotor
NSC National Security Council
NSFS naval surface fire support
NSN national stock number; NATO stock number
NTDR Near-Term Digital Radio
nuc nuclear
nuc atk nuclear attack
nuc wpn nuclear weapon
NVD night vision device
NVG night vision goggles
nw network
obj objective
obs obstacle
obsn observation
obsn hel observation helicopter
OCA offensive counterair
OCAR Office of the Chief, Army Reserve
OCE Office of the Chief of Engineers
OCO offensive cyberspace operations
OCP operational camouflage pattern
OCS officer candidate school
OCSA Office of the Chief of Staff, US Army
OD officer of the day
OD olive drab
OF Operating Force (s)
off officer
OOD officer of the deck
op operation
OP observation post