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Terms starting with U



See also


The Unified Modeling Language, a notation and specification for modeling software systems in an Object-Oriented manner.

You can read more about UML on the OMG home page or in our UML Tutorial.

UML Diagrams

Diagrams used to model different aspects of the system under development. They include various elements and connectors, all of which have their own meanings and purposes.

UML 2.5 includes 14 diagrams: Use Case diagram, Activity diagram, StateMachine diagram, Timing diagram, Sequence diagram, Interaction Overview diagram, Communication diagram, Package diagram, Class diagram, Profile diagram, Object diagram, Composite Structure diagram, Component diagram and Deployment diagram.

UML Toolbox

The main toolbar running down the center of Enterprise Architect from which you can select model elements to insert into diagrams. This is also known as the Diagram Toolbox and the Object toolbar.


A placeholder for a type or types whose implementation is not specified by the UML. Every uninterpreted value has a corresponding string representation.

Any ( CORBA )


A dependency in which one element (the client) requires the presence of another element (the supplier) for its correct functioning or implementation.


A connector that indicates that one element requires another to perform some interaction. The Usage relationship does not specify how the target supplier is used, other than that the source client uses it in definition or implementation.

Use Case

A UML model element that describes how a user of the proposed system interacts with the system to perform a discrete unit of work. It describes and signifies a single interaction over time that has meaning for the end user (person, machine or other system), and is required to leave the system in a complete state: either the interaction completed or was rolled back to the initial state.

Use Case Diagram

A diagram that captures Use Cases and Actor interactions. It describes the functional requirements of the system, the manner in which outside things (Actors) interact at the system boundary, and the response of the system.

Use Case Estimation

The technique of estimating project size and complexity based on the number of Use Cases and their difficulty.

Use Case Instance

The performance of a sequence of actions being specified in a Use Case. An instance of a Use Case.

Use Case Model

A model that describes a system's functional requirements in terms of Use Cases.


A stereotype that groups global variables and procedures in the form of a Class declaration. The utility attributes and operations become global variables and global procedures, respectively.

A utility is not a fundamental modeling construct, but a programming convenience.