Glossary Page



A relational table (composed of columns).

tagged value

The explicit definition of a property as a name-value pair. In a Tagged Value, the name is referred to as the tag. Certain tags are predefined in the UML; others can be user defined. Tagged Values are one of three extensibility mechanisms in UML.

See also: constraint, property, stereotype


The descriptor for a Class with one or more unbound parameters.

Synonym: parameterized element, parameterized class


A pseudostate indicating that upon entry of its pseudostate, the State Machine's execution ends.

thread [of control]

A single path of execution through a program, a dynamic model, or some other representation of control flow. Also, a stereotype for the implementation of an active object as a lightweight process.

See also: active object, process, concurrency

time event

An event that denotes the time elapsed since the current state was entered.

See also: event

time expression

An expression that resolves to an absolute or relative value of time.

timing diagram

A diagram that defines the behavior of different objects within a time-scale, with visual depictions of those objects changing state and interacting over time.


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 Toolbox and the Object toolbar.

top level

A stereotype of package denoting the top-most package in a containment hierarchy. The topLevel stereotype defines the outer limit for looking up names, as namespaces 'see' outwards. For example, opTopLevelsubsystem represents the top of the subsystem containment hierarchy.


A dependency that indicates a historical or process relationship between two elements that represent the same concept without specific rules for deriving one from the other.

transient object

An object that exists only during the execution of the process or thread that created it.


A relationship between two States indicating that an object in the first State performs certain specified actions and enters the second State when a specified event occurs and specified conditions are satisfied. On such a change of State, the transition is said to fire.

See also: fire, object flow


A stereotyped Class that specifies a domain of objects together with the operations applicable to the objects, without defining the physical implementation of those objects. A type can not contain any methods, maintain its own thread of control, or be nested. However, it can have attributes and associations. Although an object can have at most one implementation Class, it can conform to multiple different types.

See also: implementation class

Contrast: interface

type expression

An expression that evaluates to a reference to one or more types.