mainframe: 
An organization's central computer system.

major carrier: 
A for-hire certificated air carrier that has annual operating revenues of $1 billion or more; the carrier usually operates between major population centers.

Management of All Logistics: 
The effective management of all costs associated with logistics functions and activities so as to minimize their sum across the product supply chain.

Manufacturing Resource Planning (MRP II): 
The process of identifying, performing a needs analysis, and committing the resources needed to produce a product.

Mar Ad:
See Maritime Administration.

marginal cost: 
The cost to produce one additional unit of output; the change in total variable cost resulting from a one-unit change in output.

Marine Cargo Insurance - Average: 
Average- A term in marine cargo insurance signifying loss or damage to merchandise.

Marine Cargo Insurance - FPA: 
FPA- Free of Particular Average. A provision in a marine cargo insurance policy that no claim shall be paid for damage to goods in the course of a voyage unless a loss is sustained that totals or exceeds a certain percentage of the value as specified in the policy. The object of such a provision is the avoidance of petty claims.

Marine Cargo Insurance - General Average: 
A loss arising out of a voluntary sacrifice made of any part of a shipment or cargo to prevent loss of the whole and for the benefit of all persons concerned.

Marine Cargo Insurance - Open Policy: 
A contract b/t an insurance company and the exporter in which all shipments made by the insured are automatically protected from the time the merchandise leaves the initial shipping point until delivery at destination.

Maritime Administration (Mar Ad): 
A U.S. government agency, not actively involved in vessel operation, that administers laws for maintenance of a merchant marine for the purposes of defense and commerce.

market dominance: 
The absence of effective competition for railroads from other carriers and modes for the traffic to which the rail rate applies. The Staggers Act stated that market dominance does not exist if the rate is below the revenue-to-variable-cost ratio of 160 percent in 1981 and 170 percent in 1983.

Master Air Waybill (MAWB): 
The bill of lading issued by air carriers to their customers.

material index: 
The ratio of the sum of the localized raw material weights to the weight of the finished product.

materials handling: 
Short-distance movement of goods within a storage area.

materials management:  
The movements and storage functions associated with supplying goods to a firm.

materials planning: 
The materials management function that attempts to coordinate materials supply with materials demand.

Materials Requirements Planning (MRP): 
The process used to determine the amount of material to purchase and when to purchase it.

matrix organization: 
An organizational structure that emphasizes the horizontal flow of authority; the company treats logistics as a project, with the logistics manager overseeing logistics costs but traditional departments controlling operations.

MAWB: 
See Master Air Waybill.

measurement ton: 
Forty cubic feet; used in water transportation ratemaking.

merger: 
The combination of two or more carriers into one company that will own, manage, and operate the properties that previously operated separately.

micro-land bridge: 
An intermodal movement in which the shipment is moved from a foreign country to the U.S. by water and then moved across the U.S. by railroad to an interior, nonport city, or vice versa for exports from a nonport city.

mileage allowance: 
An allowance, based upon distance, that railroads give to shippers using private railcars.

mileage rate: 
A rate based upon the number of miles the commodity is shipped.

mini-land bridge: 
An intermodal movement in which the shipment is moved from a foreign country to the U.S. by water and then moved across the U.S. by railroad to a destination that is a port city, or vice versa for exports from a U.S. port city.

minimum weight: 
The shipment weight the carrier's tariff specifies as the minimum weight required to use the TL or CL rate; the rate discount volume.

mixed loads: 
The movement of both regulated and exempt commodities in the same vehicle at the same time.

modal split: 
The relative use that companies make of transportation modes; the statistics include ton-miles, passenger-miles, and revenue.

MRP: 
See Materials Requirement Planning

MRP II: 
See Manufacturing Resource Planning

multinational company: 
A company that both produces and markets products in different countries.

multiple-car rate: 
A railroad rate that is lower for shipping more than one carload at a time.