Abbreviations & Definitions
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Measurement (ton of 35,3 cubic feet) or Meter 
M/D  Months after date or Malicious damage 
M/E or ME  Main Engine 
M/M  Minimum/Maximum 
M/M or MIN/MAX  Minimum / maximum 
M/R  Mate’s receipt 
M/S  Motor Ship or Mate's Receipt 
M/V  Motor vessel/merchant vessel 
M/V or MV  Motor Vessel 
M/Y  Motor yacht 
M/Y or MY  Motor yacht 
MAA  Mina Al Ahmadi 
Macro-Bridge  Also known as "land bridge:. It is the same as mini-bridge, except that it involves substitution of land transportation across the United States in place of water service, for traffic that originates and terminates outside of the United States. 
Mainstay  A stay that extends from the maintop to the foot of the foremast of a sailing ship. Currently, a thing upon which something is based or depends. 
Maintenance Platform, jack up  A jack up offshore maintenance platform 
Maintenance Platform, semi Submersible  A semi submersible offshore maintenance platform 
MAK  Maximale ArbeitsplatzKonzentrationen (maximal occupational exposure concentrations) 
Malaccamax   Malaccamax is a naval architecture term for the largest size of ship capable of fitting through the 25 metres (82 ft)-deep Strait of Malacca. 
Malpractice  A carrier giving a customer illegal preference to attract cargo. This can take the form of a money refund (rebate); using lower figures than actual for the assessment of freight charges (undercubing); misdeclaration of the commodity shipped to allow the assessment of a lower tariff rate; waiving pub- lished tariff charges for demurrage, CFS handling or equalization; providing specialized equipment to a shipper to the detriment of other shippers, etc. 
Mandamu  A writ issued by a court; requires that specific things be done. 
Manifest  a detailed summary sheet of all cargo being carried for each vessel trip; information also includes origin, destination, value, number, etc. 
Manifold  Area of a tanker featuring pipes and valves for intake and offloading of cargo. 
MAP  Mono-ammonium phosphate 
Margarines  Margarines are semi-solid or consistent fatty foods originally developed to imitate dairy butter. They therefore contain a proportion of emulsified aqueous phase similar to that found in butter. The amount of moisture permitted in margarine is limited by law to a maximum of 16% in most countries while the fat content is required to be at least 80%. The aqueous phase may contain dissolved salt and an amount of milk solids treated to impart a butter-like flavour. Permitted colour is often added to give a butter-like pale yellow. Vitamins A and D are also often added. While the original purpose in developing margarine over 100 years ago was to supplement inadequate supplies of butter, there has been considerable diversifications of margarine products, particularly in the last 30 years. The following main types can be listed - a. table margarines in packets; b. table margarines in tubs; c. tub margarine with a high content of poly-unsaturated oils; d. domestic cooking margarines; e. industrial margarines for general purposes, and f. industrial margarines for puff pastry. Nowadays, the trend is to reduce the fat content to produce spreads or ""halvarines"". 
Marine Insurance  Broadly, insurance covering loss or damage of goods at sea. Marine insurance typically compensates the owner of merchandise for losses sustained from fire, shipwreck, etc., but excludes losses that can be recovered from the carrier. 
Marine Oils  The first common source of marine oil was obtained from whales. Today, whale numbers have been reduced to insignificance. Various types of fish are caught for processing into meal and oil, for example, herring, menhaden and anchovy. After refining and partial hydrogenation fish oils, are useful ingredients for margarines and shortenings. World production is close to one million tonnes. 
Marine pollutant  Substances, articles or materials which, if released into the aquatic environment, may cause serious environmental damage. 
Maritime  Business pertaining to commerce or navigation transacted upon the sea or in seaports in such matters as the court of admiralty has jurisdiction. 
Maritime Domain  It is all areas and things of, on, under, relating to, adjacent to, or bordering on a sea, ocean, or other navigable waterway, including all maritime related activities, infrastructure, people, cargo, and vessels and other conveyances. 
Maritime Domain Awareness (MDA)  It is the effective understanding of anything associated with the global maritime domain that could impact the security, safety, economy, or environment of the United States. 
Maritime lien  A right in the propery of a ship, conferred by law for seamens wages, salvage, etc. 
Maritime Security and Safety Information System (MSSIS)  It shares and displays vessel Automated Identification System (AIS) data real–time with multiple international users through a web–based, password–protected system. 
Maritime Waterways  Inland waterways linked to the sea, basically used for the traffic of seagoing vessels and designated as such under national law 
Mark I  WW designation for ro-ro carriers built in 1978-79 
Mark II  WW designation for ro-ro carriers built in 1984 
Mark III  WW designation for ro-ro carriers built in 1996 
Mark IV  WW designation for ro-ro carriers built in 2000-01 
Market related  see FLOATING PRICE 
Markets  Markets for oleochemicals continue to evolve, with niche markets developing continually. Nonetheless, the main end-use markets include building auxiliaries, candles, cleaning agents, cosmetics, detergents, fire extinguishing agents, flotation agents, food emulsifiers, insecticides, pharmaceuticals, plastics, rubber, soaps and detergents, textiles and tyres. 
Marking  Letters, numbers, and other symbols placed on cargo packages to facilitate identification. Also known as marks. 
Marlinespike  A pointed metal spike, used to separate strands of rope in splicing. 
MARPOL  The abbreviated term for the International Convention for the Prevention of Pollution by Ships (MARine POLlution) The International regulations concerning the construction of vessels and procedures to be followed to prevent pollution of the sea by oil, no 
MARPOL 73/78  International Convention for the Prevention of Pollution from Ships, 1973, as modified by the Protocol of 1978 relating to the International Convention for the Prevention of Pollution from Ships, 1978  
Marpol Category  The Pollution Category (X, Y, Z) assigned to each product under Annex II of MARPOL 73/78. OS means the product was evaluated, and found to fall outside the categories X, Y, or Z. I indicates that the product is an Annex 1 product. 
MARPOL Pollution Category  This refers to the pollution categories designated in the “MARPOL 73/78” regulations: X to Z - Pollution category of the cargo as evaluated by MARPOL. “X” means highest environment impact OS - Pollution category is evaluated, but outside categories X to Z. Annex I - Included in 'List of Oils' 
MARS  Nautical Institute Marine Accident Reporting System 
MarView  It is an integrated, data–driven environment providing essential information to support the strategic requirements of the United States Marine Transportation System and its contribution to economic viability of the nation. 
Mass explosion  Explosion which affects almost the entire load virtually instantaneously. 
Master  An officer qualified to command a ship. Usually refers to the Captain. 
Master Inbound  U.S. Customs’ automated program under AMS. It allows for electronic reporting of inbound (foreign) cargoes in the U.S. 
Mate’s Receipt  An archaic practice. An acknowledgement of cargo receipt signed by a mate of the vessel. The possessor of the mate’s receipt is entitled to the bill of lading, in exchange for that receipt. 
MATS  Material(s) 
MAX  Maximum 
MAXBACTAP  Max But As Close To As Possible 
MB  Merchant Broker 
MB/T  Motor blocks/ turnings 
MBL  Minimum Breaking Load 
MBM  Multi-Buoy Moorings 
MBM  1,000 board feet. One MBM equals 2,265 C.M. 
MBTE  Methyl tert-butyl ether 
MCFS  Master Container Freight Station. See CFS. 
MCO  Maximum continous output 
MCR  Maximum Continuous Rating - Maximum warranted power an engine can sustain under continuous operation. 
MCS  Maritime Security Code 
MCT  Medium-Chain Triglyceride. Triglycerides containing fatty acid chains of 6-10 carbon atoms which are readily absorbed by the body. 
MDO  Marine diesel oil 
MDO  Marine diesel oil 
MDO or DO  Marine diesel oil 
MDSE  Merchandise 
MDWT  Metric DeadWeight Tons 
ME  Main Engine 
MEA  Monoethanolamine 
Measurement Cargo  Freight on which transportation charges are calculated on the basis of volume measurement. 
Measurement Ton  40 cubic feet. 
MECH  Mechanical 
Mechanical Lift Dock  A lifting dock facility using winches to lower and raise platform 
Mechanically Ventilated Container  A container fitted with a means of forced air ventilation. 
Mechanism of toxicity  The way in which a chemical alters basic biological functions and structures in order to exert its toxic effect(s) 
MED  Mediterranean 
Medium-speed diesel  Moderately large diesel engines such as those which propel large boats and heavy-duty locomotives. These engines burn a heavy gasoil which sometimes takes their name. 
MEG  Middle East Gulf 
Megaports Initiative  It is a National Nuclear Security Administration (NNSA) initiative, started in 2003. It teams up with other countries to enhance their ability to screen cargo at major international seaports. The Initiative provides radiation detection equipment and trains their personnel to specifically check for nuclear or other radioactive materials. In return, NNSA requires that data be shared on detections and seizures of nuclear or radiological material that resulted from the use of the equipment provided. 
MEK  Methyl Ethyl Ketone 
Melting  When heated sufficiently, a solid changes state to a liquid. The melting of a fat depends on its previous triglyceride composition. The baking or spreading performance of commercial fats depends greatly on their melting behaviour. Solid fat content measurement is commonly used to monitor this behaviour. 
MEM  Moment 
MEMO  Memorandum 
Memorandum Bill of Lading  An in–house bill of lading. A duplicate copy. 
Memorandum Freight Bill  See Multiple Container load Shipment. 
MeOH  Methyl Alcohol = Methanol 
MEPC  Marine Environment Protection Committee 
Mercaptans  Mercaptan sulfur. Excessive concentrations of these malodorous organic sulfur molecules make motor gasoline unmerchantable. Blenders, therefore, want to know the mercaptan content of components they could consider buying. The kerosene trade pays careful attention to this form of sulfur too. Jet fuel, and sometimes burning kerosene, have mercaptans limits. 
merger  The joining of two or more (shipowning) companies 
MESA  Most Environmentally Sensitive Area 
MESSRS  Messieurs or Gentlemen or Sirs 
Metacenter or transverse metacenter  Ship Stability: The highest point to which G may rise and still permit the vessel to have positive stability. Found at the intersection of the line of action of B when the ship is erect with the line of action of B when the ship is given a small inclination. 
Metals content  A specification of concern to buyers of fuel oil and vacuum gasoil.Heavy metals, such as nickel, vanadium, and copper, poison cat-cracking catalysts.Most refiners specify a maximum metals limit for the catfeed and vacuum unit feedstock they would consider purchasing.Traces of metal, particularly lead, also worry reformer feedstock buyers. 
Metaxylene  Metaxylene is an isomer of mixed xylene. It is used as an intermediate in the manufacture of polyesters for coatings, inks, reinforced plastics, and packaging applications. 
Meter  39.37 inches (approximately). 
Methaemoglobin generator  A substance capable of converting the oxygen carrying molecule (haemoglobin) in the red blood cell to an oxidized form (methaemoglobin), which has a reduced capacity to transport oxygen.  
Methane  A colorless, odorless, flammable gas that occurs abundantly in nature as the chief constituent of natural gas, as a component of firedamp in coal mines, and as a product of the decomposition of organic matter. Methane is used as a fuel and as a starting material in chemical synthesis. 
Methanol  Methanol, a colorless alcohol, is a chemical used in the production of formaldehyde, acetic acid and methyl methacrylate (MMA), and is used as a solvent in many applications. It is also used to produce MTBE. 
Methyl Esters  The fatty acid composition of an oil is normally determined by using Gas Liquid Chromatography of the fatty acid methyl esters (FAME analysis). The methyl ester derivatives of fatty acids are comparatively volatile. Methyl esters of fatty acids are conveniently prepared by displacing the glycerol from the triglycerides of the oil, using methanol in the presence of an alkaline or acidic catalyst. 
Methylamines  Methylamines (mono-, di- and tri) and their derivatives are alkaline substances that are produced by reacting ammonia and methanol, in the gas phase at high temperatures and high pressure. Methylamines are available as anhydrous liquefied gases and as aqueous solutions. 
Metric Ton  2,204.6 pounds or 1,000 kilograms. 
MEX  Mexico 
MF  Medium Frequency 
MFAG  Medical First Aid Guide 
MFG  Manufacturing 
MFRS  Manufactures 
MG/R  Managing/Manager 
MGA  Master''s general account 
MGO  Marine gas oil 
MGT  Management 
MH  Main hatch 
MHE  Materials handling equipment 
MHHW  Mean Higher High Water 
MHI  Car carriers built at Mitsubishi Heavy Industries in 2004-06 
MHW  Mean High Water 
MHWN  Mean high water neaps: and 
MHWS  Mean High Water Spring Tides 
MIAP  Mortgagee interest additional perils pollution 
MIBK  Methyl Isobutyl Ketone 
MIC  Man-In-Charge 
Micro-Bridge  Interior point intermodal service similar to mini-bridge, except that cargo originates or terminates at an inland city rather than another port city. The cargo moves on a single (ocean) bill of lading to and from the interior point and the port. 
Microbridge  A cargo movement in which the water carrier provides a through service between an inland point and the port of load/discharge. The carrier is responsible for cargo and costs from origin on to destina- tion. Also known as IPI or Through Service. 
MICS  Member of The Institute of Chartered Shipbrokers, London 
MID  Middle 
Mid-point  The temperature where 50 percent (weight or volume basis, as specified) of a natural material or refined product has boiled.Sometimes called 50 percent point. 
Middle distillates  Products heavier than motor gasolinenaphtha and lighter than residual fuel oil.This range includes heating oil, diesel, kerosene, and jet kero. 
Midship  Approximately in the location equally distant from the bow and stern  
MII  Mortgagee interest insurance  
Mile  A unit equal to 5,280 feet on land.A nautical mile is 6076.115. 
Mill Scale  A thick oxide coating formed on the steel when heated, e.g., in connection with hot working or heat treatment 
MIN  Minute or Minimum 
MIN/MAX  Minimum/Maximum (cargo quantity) 
MIN/MAX OR  Minimum / maximum 
Minehunter  A naval vessel equipped for detecting explosive marine mines 
Minelayer  A naval vessel designed for laying marine mines 
Minesweeper  A naval vessel equipped for detecting, destroying, removing, or neutralizing explosive marine mines 
Mini Landbridge  An intermodal system for transporting containers by ocean and then by rail or motor to a port previously served as an all–water move (e.g., Hong Kong to New York over Seattle). 
Mini-Bridge  Substitution of rail or truck service for water transportation between two U.S. port cities for cargo originating or terminating in a port city. 
Minimum Bill of Lading  A clause in a bill of lading which specifies the least charge that the carrier will make for issuing a lading. The charge may be a definite sum or the current charge per ton for any specified quantity. 
Minimum Charge  The lowest charge that can be assessed to transport a shipment. 
Mining Vessel  A vessel equipped for offshore mining operations, most commonly diamonds 
MIO  Millon(s) 
MIP  Marine insurance policy 
MISC  Miscellaneous 
Miscible  In this guidebook, means material that mixes readily with water. 
Mission Ship  A mobile vessel used for missionary work 
MITI  Ministry of International Trade & Industry (JP) 
Mixed Container Load  A container load of different articles in a single consignment. 
MKT  Market 
ML  Motor launch 
MLB  Mini-landbridge 
MLC  Meters of Liquid Column 
MLD  Moulded 
MLLW  Mean low low water 
MLS  Miles 
MLW  Mean low water 
MLWN  Mean low water neaps. Average depths of water available at the times of low and of high tides during periods of Neap Tides 
MLWS  Mean Low Water Spring Tides 
MM  Marketing Manual 
MM  Engine Room (OCIMF acronym) 
mm  millimetre 
MMA  Methyl Methacrylate. A chemical derived from propylene, used for the manufacture of polymethyl methacrylate and also for polymer dispersions and other resins. 
MMFB  Middlewest Motor Freight Bureau. 
MMPD  Maximum Most Probable Discharge 
MMS  APPE Monthly Monitoring of Monomers. APPE is a major group within the Association of Petrochemicals Producers in Europe (APPE). For more information, click here. 
MMSI  Maritime Mobile Selective Call Identity Code 
MNLO  Merchant Navy Liaison Officer 
MO  Managing Owner 
MOA  Memorandum of Agreement: A contract form specifying the terms and conditions covering the sale and purchase of a merchant ship 
MOD  Ministry of Defence 
Modified Atmosphere  A blend of gases tailored to replace the normal atmosphere within a container. 
MODU  Mobile Offshore Drilling Units 
Mogas  An abbreviation of motor gasoline. 
MOH  Medical Officer of Health 
Moisture  Since water is only very slightly soluble in fats, it is present only in small amounts and is referred to as moisture. Moisture in oils and fats may be determined by drying, distillation, absorption or titrimetry. The presence of water, especially when in large amounts, may enhance hydrolysis especially at elevated temperatures. 
MOL  More or Less 
Molasses Tanker  A tanker for the bulk carriage of molasses 
MOLCHOP  More Or Less CHarterers OPtion 
MOLCHOPT  More or less in Charterers option 
MOLCHOPT or MOLCO  More or Less Charterers Option 
MOLCO  More or less Charterers option 
Molecule  Chemical combination of two or more atoms of the same chemical element (such as O2 - which is Oxygen) or different chemical elements (such as H2O - which is water). 
MOLOO  More or less in owners' option 
Molten Sulphur Tanker  A tanker for the bulk carriage of molten sulphur in insulated tanks at a high temperature 
MOM  Moment 
Moment  Ship Stability: The product of two numbers, for example the force or weight moved multiplied by a distance 
MON  MONitors (fire) 
MON (Motor Octane Number)  A rating of the anti-knock properties of a finished motor gasoline or blendstock. The test determines MON simulates demanding engine operating conditions such as substantial loads and high speeds. The MON method yields lower numbers than the RON (research octane number) test which reflects milder conditions. 
Monoglyceride (Monoacylglycerol)  Monoglyceride is a compound used as an emulsifier in margarine/peanut butter etc, to help the uniform dispersion of oil in water. Monoglycerides do not occur naturally in appreciable quantities except in fats and oils that have undergone partial hydrolysis. For instance, fats and oils that are damaged or spoiled in the field or in storage and have abnormally high free fatty acid contents will have corresponding high di- or monoglyceride content. 
Monomer  A molecule that can combine with others to form a polymer. 
Monomer  One molecular unit which links with others of its own or a similar kind to form a Styrene monomers, for instance, connect to form the familiar plastic, polystyrene. 
Monounsaturated  A fatty acid containing only one pair of carbon-carbon double bonds. 
Montreal Protocol  International agreement which aims to protect the ozone layer. Forms part of the UN Environmental Programme (UNEP)  
Mooring  An arrangement for securing a ship to a mooring buoy or pier 
Mooring Buoy  A mooring buoy 
Mooring Vessel  A vessel equipped to assist with the mooring and/or anchoring of larger vessels. Typically it will have a frame to prevent the ropes and chains fouling on the superstructure 
Mooring Vessel, Naval Auxiliary  A naval auxiliary vessel designed to assist with the mooring and or anchoring of larger vessels 
MOP  Muriate of Potash 
MOS  Months 
MOS or MTHS  Months 
MOT  Ministry of Transport or Monthly Overtime 
Motor alkylate  Full name of a gasoline blendstock often simply called alkylate. 
Motor gasoline  Petroleum-derived fuel blend intended to power spark-ignited internal combustion automobile engines. This propellant's boiling range can span C4 through 430 F. In practice, it usually has a somewhat lower end point. Mogas must meet various specifications depending on the where and when it sells. Governments, climates, seasons, and market organizations all impose quality restrictions on the product. Most grades intended for modern motors resemble the fuel described by ASTM D 439. Mogas differs in some respects from aviation gasoline (avgas) a mixture blended for internal combustion aeroplane engines 
MOU  Memorandum of Understanding 
MOU PARIS  Memorandum of Understanding (Paris) 
MP  Propylene Glycol Methyl Ether 
MPA  Propylene Glycol Methyl Ether Acetate 
MPG  Monopropylene Glycol. Produced by reacting propylene oxide with water. Monopropylene glycol is widely used for its solvent properties in the pharmaceutical, food, flavor and personal care industries. It is more widely used as an anti-freeze/de-icer, grinding aid, heat transfer fluid, component in hydraulic fluids, humectant, and surface coating industries. 
MPG / USP  Pharmaceutical grade monopropylene glycol 
MPH  Miles per hour 
MPP  Multi-purpose (type of ship) 
MR  Medium Range (tanker): A vessel designed for carrying refined petroleum products in bulk tanks (25,000 dwt - 44,999 dwt approx). MR tankers primarily transport refined oil products on intra-regional routes between the oil refineries. Only on rare occasions are they employed over longer distances. 
MRA  Marine Response Alliance 
MRNG  Morning 
MRV  Monitoring Reporting and Verification 
MRX  Medium range cross-purpose tanker 
MS  Months after sight or Machinery survey 
MSA  Merchant Shipping Act or Mine Safety Appliances 
MSC  Manchester Ship Canal; Maritime Safety Committee 
MSDS  Material Safety Data Sheet 
MSG  Methacrylates Sector Group, a sector group of the Association of Petrochemicals Producers in Europe (APPE). For more information, click here. 
MSL  Mean Sea Level 
MSM  Minimum safe manning (flag states minimum approved manning for a vessel) 
MSO  Marine Safety Office (U.S. Coast Guard) 
MSP  A U.S. Department of Transportation program that helps to assure sufficient sealift to support the United States Armed Forces and U.S. emergency sealift needs, using commercial ships. 
MSRC  Marine Spill Response Corporation 
MSS  Maritime Safety and Security 
Mst  Measurement 
MSV  Motor support vessel 
MT  Mean Time or Metric Tons 
MT or MTONS or MTS  Metric Tonnes 
MT, M.T. or M/T  Refers to any self-propelled tanker, i.e. tanker fitted with diesel engine for propulsion. 
MTBE  MTBE is not covered under the chemical code and thus is not subject to the exemptions for carriage of chemicals. MTBE has become a large trade and is often carried in oil vessels as well as chemicals ones. The product is volatile and there is no technic 
MTL  Mean tidal level 
MTO  Multimodal transport operator 
MTONS  Metric Tonnes 
MTOTS  Marine Terminal Operators Training System 
MTPA  Million metric tonnes per annum 
MTSA  The Maritime Transportation Security Act of 2002, is designed to protect ports and waterways from terrorists attacks. The law is the U.S. equivalent of the International Ship and Port Facility Security Code(ISPS), and was fully implemented on July 1, 2004. It requires vessels and port facilities to con- duct vulnerability assessments and develop security plans that may include passenger, vehicle, and baggage screening procedures; security patrols; establishing restricted areas; personnel identification procedures; access control measures; and/or installation of surveillance equipment. 
MTSC  Marine Technical Sub-Committee 
Multimodal  Synonymous for all practical purposes with “Intermodal.” 
Multipurpose ship  General cargo ship which can also carry containers 
MultiTank Container  A container frame fitted to accommodate two or more separate tanks for liquids. 
Munitions Carrier  A naval auxiliary Vessel for the carriage of munitions 
Museum, Stationary  A stationary vessel of interest preserved as a museum exhibit. 
Mutagen  An agent that causes biological mutation 
MV  Merchant Vessel: A vessel propelled by an engine 
MWC  Meter Water Column 
Myristic Acid  Myristic acid (C14:0) is a saturated intermediate chain length fatty acid found mainly in coconut, palm kernel and milk fats. It is also a minor constituent of most animal and vegetable fats.