m Metre
M/T Metric tons (2,250 lbs.). 2. abbreviation for empty
M/V merchant vessel
Mafi Trailer German brand name of a roll trailer used for RoRo purposes.
Magnetic north The direction to which a compass points. Magnetic north differs from true north because the magnetic fields of the planet are not exactly in line with the north and south poles. Observed differences between magnetic and true north is known as magnetic variation.
MAIB Marine Accident Investigation Branch
Maiden Trip First voyage of a vessel or aircraft after delivery from new-building to her owner(s).
MAIIF Marine Accident Investigators' International Forum
Main- Prefix refering a component of the mainmast... maintop, mainchains, main backstay, etc.
Main Carriage The primary stage in the movement of cargo from the point of origin to the intended final destination.
Main Deck The uppermost complete deck.
main deck The principal deck of a ship. In ships with multiple decks, the deck beneath the spar deck.
main mast The tallest (possibly only) mast on a boat.
main sheet The line used to control the mainsail.
main topsail A topsail on the main mast.
mainchains Heavy steel plates fastened to a ship's sides that anchor the rigging for the mainmast.
Main-line Operator A carrier employing vessel(s) in the main or principal routes in a trade but not participating within a consortium.
mainmast The principal mast of a sailing ship.
Mainmast Centermost, and generally highest, mast.
mainmast Aboard the three-masted Concordia, the middle of the three
Mainsail The sail set on the mainmast.
Mainsail The main sail that is suspended from the main mast.
Mainsheet the line that controls the boom
Maintenance Chain A sequence of events in a goods flow which preserves and/or restores the value of a specific good. This may include repairs.
Make fast To secure a line
Make way Moving through the water.
Manifest Document, which lists the specifications of goods, loaded in a means of transport or equipment for transportation purposes.
MANNING SCALES The minimum number of officers and crew members that can be engaged on a ship to be considered as sufficient hands with practical ability to meet every possible eventuality at sea.
Manufacturers Plate A plate indicating the name and address of the container manufacturer and particulars of the container.
Manufacturing Process The producing of goods or wares by manual labour or machinery, often on a large scale and with division of labour.
Manufacturing Resource Planning A method for the effective planning of a manufacturing company, being a direct out-growth and extension of MRP-I.
Marconi An alternative name for bermudan
Marina A place where boats can find fuel, water and other services. Marinas also contain slips where boats can stay for a period of time.
Marina: A normally enclosed area safe from flooding or inclement weather.
Marine Insurance Policy An insurance policy protecting the insured against loss or damage to his goods occurred during ocean transport.
Mariner: In general, a person employed in a sea-going vessel. In some cases, applied to a seaman who works on deck.
Marisat maritime satellite system
MARITIME ADMINISTRATION (MARAD ) Oversees subsidy programs to the United States Merchant Marine. Assigns routes to subsidized liners.
MARITIME LIEN A claim which attaches to the res, i.e., the ship,. freight, or cargo.
MARITIME SUBSIDY BOARD (MSB) A branch within the Maritime Administration which deals with Operating Differential Subsidy and Construction Differential Subsidy.
Mark An object used as a reference point while navigating
Market Analysis Systematic investigation of the growth and the composition of a market.
Marketing The process of organising and directing all the company activities which relate to determining the market demand and converting the customers buying power into an effective demand for a service and bringing that service to the customer.
Marline spike A pointed tapering iron or wooden spike used for opening strands of rope
Marlinespike A pointed tool used to separate the strands of a rope or wire.
MARLINSPIKE A tool for opening the strands of a rope while splicing.
MARLINSPIKE A tool for opening the strands of a rope while splicing.
MARPOL 73/78 The International Convention for the Prevention of Pollution from Ships, 1973, as modified by the Protocol of 1978.
Marpol 73/78 International Convention for the Prevention of Pollution from Ships,IMO
Marry the Gunner's Daughter: Old Navy nickname for a flogging, particularly when across a gun.
Mast Any vertical pole on the boat that sails are attached to. If a boat has more than one mast, they can be identified by name.
Mast step A recess or fitting in a vessel's keel into which the base of the mast is positioned
Master The person in charge of a vessel. The captain.
master The captain of a merchant ship.
Master Data The set of data that is needed to establish sufficient reference material to support the maximum use of pre-coded, pre-agreed information enabling more efficient transaction messaging.
Master Production Schedule A realistic, detailed, manufacturing plan for which all possible demands upon the manufacturing facilities (such as available personnel, working hours, (management) policy and goals) have been considered and are visualised. The MPS is a statement of what
Master's Mates Warrant officers assisting the master.
Masthead The top of a mast.
MASTHEAD LIGHT A white light positioned over the fore and aft centerline of the vessel.
Masthead sloop A sloop whose headstay reaches the mast head
Masts Vertical spars that carry the yards. From the bow, they are the Foremast, Mainmast, and Mizzenmast. Each was composed of a lower mast, a topmast, and a t'gallant mast
mate A deck officer ranking below the master on a merchant ship.
Material Requirements Planning An inventory and purchasing planning system that integrates product components, lead times and deadlines.
Materials Handling The activities of loading, unloading, placing and manipulating material and of in-process movement.
Materials Management The planning and control of the activities related to the materials flow from the suppliers up to the end of the conversion/production process.
Mate's Receipt A document signed by the chief officer of a vessel acknowledging the receipt of a certain consignment on board of that vessel. On this document, remarks can be made as to the order and condition of the consignment.
Mayday An internationally recognized distress signal used on a radio to indicate a life-threatening situation. Mayday calls have priority over any other radio transmission and should be used only if there is an immediate threat to life or vessel. More urgent than a pan pan or securite call.
MAYDAY Spoken international distress signal, repeated three times
Mb megabyte
MCA Marine Coastguard Agency
MCC mission control centre
MDO marine deisel oil
Meander: A bend in the middle and lower course of a River.
Means of Transport Type of vehicle used for the transport of goods (e.g. aircraft, barge, truck, vessel or train).
Measurement Ton A ton of one cubic metre water.
Mechanics Lien The legal enforceable claim, which a person who has performed work or provided materials is, permitted to make against title to the property or as a preferential person in the event the estate or business is liquidated.
MEDEVAC medical evacuation Evacuation of a person for medical reasons
Medical First Aid Guide Instructions to be consulted in case of accidents involving dangerous goods.
MEDICO Medical advice usually by radio.
MEO medium earth orbit (satellite configuration)
MEPC Marine Environment Protection Committee, IMO
Mercator projection A form of map
Merchant For cargo carried under the terms and conditions of the Carrier's Bill of Lading and of a tariff, it means any trader or persons (e.g. Shipper, Consignee) and including anyone acting on their behalf, owning or entitled to possession of the goods.
Merchant Haulage Inland transport of cargo in containers arranged by the Merchant.
Meridian A longitude line. Meridians are imaginary circles that run through both poles.
MERSAR Merchant Ship Search and Rescue Manual
Mess Men grouped for feeding purposes. The "Officer's Mess" was the wardroom. Groups of eight or so seamen were grouped as a "mess," and one designated the "mess cook." At mealtimes, the mess cook would fetch the food for his mess.
Messenger A small line used to pull a heavier line or cable. The messenger line is usually easier to throw, lead through holes or otherwise manipulate than the line that it will be used to pull.
Meta-centric Height The distance between the centre of gravity of a vessel and a fictitious point. If the metra- centric height is zero or negative, the vessel will heel or capsize.
Meter class a measurement rule for for rating boats
MF medium frequency MHz megahertz
MFN Most Favored Nation.
MGN  Marine Guidance Note
MGO Marine Gas Oil
MIB Marine Index Bureau.
MICROBRIDGE A system of through rates and service offered by a carrier for cargo shipments from any inland U.S. location to a port, by sea to a foreign port and finally overland to foreign inland destination.
Middle Ground: Shoal area between two navigational channels.
Midship In the middle portion of the boat
Midshipman The lowest rank of officer aboard ship. Service as midshipman for a number of years was required before applying for a commission.
Millibar A unit of barometric pressure
MINILAND BRIDGE The process of taking inland cargo bound for export to the coast by rail and loading it directly to the ship.
Minimum Charge The lowest amount which applies to the transport of a consignment, irrespective of weight or volume.
Minimum Inventory The planned minimum allowable inventory for an independent demand item.
Minor Unit Unit of recorded value (i.e. as recorded by banks) which is a division of the respective unit of currency.
MIRAID Maritime Institute for Research and Industrial Development.
MIS management information system
Mixed Consignment A consignment of different commodities, articles or goods, packed or tied together or contained in separate packages.
MIXED SHIPMENT A shipment consisting of more than one commodity, articles described under more than one class or commodity rate item in a tariff.
Mizzen the shorter mast behind the main mast on a ketch or yawl
Mizzen- Prefix refering a component of the mizzenmast... mizzenchains, mizzen backstay, etc.
mizzen mast A smaller aft mast on a ketch or yawl rigged boat.
mizzen sail The sail on the aft mast of a ketch or yawl rigged sailboat.
mizzen staysail A small sail that is sometimes placed forward of the mizzen mast.
Mizzenmast Aftmost mast, often the smallest of the three.
MNI Member of The Nautical Institute
Mode of Transport Method of transport used for the conveyance of goods, (e.g. by rail, by road, by sea).
Model A representation of a process or system that attempts to relate the most important variables in the system in such a way that analysis of the model leads to insights into the system.
MODU Mobile Offshore Drilling Unit.
Module A separate and distinct unit of hardware or software that may be used as a component in a system.
Monohull A boat that has only one hull, as opposed to multihull boats such as catamarans or trimarans.
Moor: To secure a ship in position by two or more anchors and cables. 2. To attach a vessel to a buoy, or buoys. 3. To secure a vessel by attaching ropes to positions ashore.
Mooring Any arrangement of anchors and rodes that are permanently set
Mooring A place where a boat can be moored. Usually a buoy marks the location of a firmly set anchor.
mooring bitt A strong pair of iron, steel or wooden posts on a ship's deck, around which ropes or cables are wound and held fast.
mooring buoy A buoy marking the location of a mooring. Usually attached to an anchor by a small pendant.
MOORING LINE A cable or line to tie up a ship.
Mooring line A line used to secure a boat to an anchor, dock, or mooring.
Mooring pins: Spikes that are driven into the bank to allow mooring were no mooring rings or bollard's are available.
MOP mobile offshore production
Morse code A code that uses dots and dashes to communicate by radio or signal lights.
Motor 1) An engine.2) The act of using an engine to move a boat.
motor sailer A boat designed to use its motor for significant amounts of time and use the sails less often than a normal sailboat.
Motor: The name given to a boat towing a 'Butty'.
MOU memorandum of understanding (often refers to PSC)
Mount 1) An attachment point for another object.2) The act of putting an object on its mount.
Movement The act or process of changing the position of an object and or people.
Movement Inventory The inventory during a production process caused by the time required to move goods from one place to another.
MRCC maritime rescue coordination centre
MSB Maritime Subsidy Board.
MSC Marine Safety Committee, IMO
MSI maritime safety information
MSN merchant shipping notice 'M- Notice',UK
MTC Maritime Transport Committee, OECD
Multi Purpose Vessel Vessel designed for the carriage of different types of cargo: general, bulk, heavy and/or containerised cargo.
Multihull Any boat with more than one hull, such as a catamaran or trimaran.
Multimodal Transport The carriage of goods (containers) by at least two different modes of transport.
Multimodal Transport Operator/Carrier The person on whose behalf the transport document or any document evidencing a contract of multimodal carriage of goods is issued and who is responsible for the carriage of goods pursuant to the contract of carriage.
Multiple Sourcing Selecting of and working with more than two equivalent suppliers for a certain product.
MULTIPURPOSE SHIP Any ship capable of carrying different types of cargo which require different methods of handling. There are several types of ships falling into this category, for example, ships which can carry roll on/roll off cargo together with containers.
mushroom anchor A type of anchor with a heavy, inverted mushroom-shaped head. Mushroom anchors are used to anchor in mud and other soft ground.