M (Glossary)

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The support of a software system after it is deployed.


A relationship that indicates that the artifact source embodies the target model element. Stereotypes can be added to Enterprise Architect to classify the type of manifestation of the model element.


Messages indicate a flow of information, or transition of control, between elements. Messages are used by Communication diagrams, Sequence diagrams, Interaction Overview diagrams and Timing diagrams.

message endpoint

An element that defines an endpoint of a Lifeline, such a State or Value Lifeline in a Timing diagram.

message label

Used for messages sent between lifelines to make the diagram appear less cluttered. Labels with the same name indicate that a message can be interrupted.


A class whose instances are classes. Metaclasses are typically used to construct metamodels.


A vector-based image format native to Windows. Supports high detail and excellent scaling. Typically used for saving diagram images for placement in documents. Comes in Placeable (an older format) and Enhanced (current standard format).


A model that defines the language for expressing a metamodel. The relationship between a meta-metamodel and a metamodel is analogous to the relationship between a metamodel and a model.


A model that defines the language for expressing a model.


A generic term for all metaentities in a metamodeling language. For example, metatypes, metaclasses, metaattributes, and metaassociations.

Meta-Object Facility (MOF)

An Object Management Group (OMG) standard. MOF originated in the UML, when the OMG required a Meta-Modeling architecture to define the UML. MOF is designed as a four-layered architecture.


The implementation of an operation. It specifies the algorithm or procedure associated with an operation.

model [MOF]

An abstraction of a physical system with a certain purpose.

See also: physical system

Usage note: In the context of the MOF specification, which describes a meta-metamodel,  the meta-metamodel is for brevity frequently referred to simply as the model.

model aspect

A dimension of modeling that emphasizes particular qualities of the metamodel. For example, the structural model aspect emphasizes the structural qualities of the metamodel.

model elaboration

The process of generating a repository type from a published model. Includes the generation of interfaces and implementations which enables repositories to be instantiated and populated based on, and in compliance with, the model elaborated.

model element [MOF]

An element that is an abstraction drawn from the system being modeled.

Contrast: view element. In the MOF specification model elements are considered to be metaobjects.

model library

A stereotyped package that contains model elements which are intended to be reused by other packages. A model library differs from a profile in that a model library does not extend the metamodel using stereotypes and tagged definitions. A model library is analogous to a class library in some programming languages.

modeling time

Refers to something that occurs during the modeling phase of the software development process. It includes analysis time and design time.

Usage note: When discussing object systems, it is often important to distinguish between modeling-time and run-time concerns.

See also: analysis time, design time

Contrast: run time


A software unit of storage and manipulation. Modules include source code modules, binary code modules, and executable code modules.

See also: component


Meta-Object Facility, an Object Management Group (OMG) standard. MOF originated in the UML, when the OMG required a Meta-Modeling architecture to define the UML. MOF is designed as a four-layered architecture.

multiple classification

A semantic variation of generalization in which an object can belong directly to more than one classifier.

See also: static classification, dynamic classification

multiple inheritance

A semantic variation of generalization in which a type can have more than one supertype.

Contrast: single inheritance


A specification of the range of enableable cardinalities that a set can assume. Multiplicity specifications can be given for roles within associations, parts within composites, repetitions, and other purposes. Essentially a multiplicity is a (possibly infinite) subset of the non-negative integers.

Contrast: cardinality

multi-valued [MOF]

A model element with multiplicity defined whose Multiplicity Type:: upper attribute is set to a number greater than one. The term multi-valued does not pertain to the number of values held by, for example, an attribute or parameter at any point in time.

Contrast: single-valued