- Motor Vessel
- mountain railway
- mourning flag
- movement regime
- moving carpet
- moving pavement
- moving walkway
- mudflats
- multichannel monitoring
- multiple taxation
- mooring
- mooring berth
- mooring gear
- mooring pile
- moving floor
- moving sidewalk
- multipurpose carrier
- multipurpose ship
- multiservice vessel
- multidecking system
- multihull ship
- multiple crossing
- multipurpose tanker
- multiskirt system
- national navy
- multistrand rope
- multitube nozzle
- mushroom ventilator
- nacelle
- natural density
- natural harbor
- naval architect
- naval architecture
- naval engineer
- navigation bridge
- navigation light
- navigational instrument
- near collision
- net proceed
- net sling
- nautical almanac
- naval
- naval dockyard
- navigable
- navigation afloat
- navigation radar
- navy
- negotiation credit
- net tonnage
- network-like
- new pattern
- night range
- night wave
- no advice
- no authorized
- no date
- no fund
- nonreusable pallet
- nonstop flight
- nominal bill
- nominal cheque
- nonstop train
- normal traffic
- northern latitude
- northern lights
- nose gear
- noseband
- not available
- notched nozzle
- nonkinking rope
- nonreserved space
- normal flange
- north
- northerly
- nose heaviness
- nosing frequency
- notched wheel
- notice
- nut retainer
- oakum
- obsolescence cost
- occluded front
- ocean liner
- ocean navigation
- oceanic basin
- off-shore
- official timetable
- offshore dock
- offshore wind
- oil pier
- oil tank
- on shore
- oil rig
- old price
- on board
- open point
- open policy
- open propeller
- open wagon
- operating ceiling