Using the glossary:
The glossary is meant to help you understand the jargon that saturates the world of object-oriented modelling and UML. Keep this guide handy and refer to it as necessary.
The 
symbol indicates that the glossary entry is Gentleware Poseidon specific.
>>> A <<<
Aggregation
An aggregation relationship is a 'whole-part' relationship, e.g. a page is a part of a book.
Association
An association is a represention of a semantic relationship between instances of objects.
Association End
An association end contains a reference to a target classifier and defines the participation of the classifier in the association.
Attribute
An attribute is a logical data value of a specified type in a class which is inherent to an object. Each object of the class separately holds a value of the type.
>>> C <<<
Class
A class is a descriptor for objects that share the same methods, operations, attributes, relationships, and behavior, representing a concept within the system being modeled.
Comment
A comment is an annotation attached to an element or a collection of elements that has no direct semantics, but may display semantic information.
Component
A component is a replaceable, tangible part of a system that realizes of a set of interfaces, including software code, scripts, or command files, run-time objects, documents, databases, etc.
Composition
A composition is a stronger form of aggregation. A part can only be a part of one composite, and the destruction of the whole automatically implies destruction of the parts. Parts with multiplicity that is not fixed can be created after the composite has been created, but once established they live and die with it. Parts can be explicitly removed before the death of the composite.
Constraint
Constraints are expressions that represent semantic conditions or restrictions that are used to limit the use of model elements.
>>> D <<<
Dependency
A dependency exists between elements and expresses that elements within one package use elements from the package on which it depends, implying that a change in one element may affect or supply information needed by the other element.
Details Pane
The Details pane is a quadrant of the Poseidon work area, located in the lower right corner, which provides advanced editing and viewing capabilities for all elements.
Diagram
A diagram is a graphical presentation of a compilation of model elements, rendered as a graph of shapes connected by paths. Comprehension resides mainly in the topology, not in the size or placement of the symbols.
Diagram Pane
The Diagram pane is the main working area of Poseidon, where all of the diagrams are displayed.
>>> E <<<
Element
An element is a broad term with little in the way of specific semantics and refers to an atomic constituent of a model.
>>> G <<<
Generalization
A generalization is a directed relationship between two like elements, where one element is the parent element and the other is the child element. This type of relationship is also referred to as 'kind of', meaning that the child is a kind of the parent.
>>> I <<<
Inheritance
An inheritance relation allows more specific elements to incorporate structures and behaviors that have been defined by more general elements.
Instance
An instance is an individual, concrete entity with its own identity and value. An object is an instance of a class, a link is an instance of an association.
Interface
An interface is a named set of operations that characterize the behavior of an element. Interfaces do not have implementations, they lack attributes, states, and associations, they have only operations. Interfaces may also be noted in lollipop and socket notations.
>>> L <<<
Label
A label is a notational term for the use of a string on a diagram.
Link
A link is an instance of an association.
>>> M <<<
Message
A message refers to the transfer of information, such as a signal or operation call, from one object to another with the expectation that activity will result. The receipt of a message instance is normally considered an instance of an event.
Method
A method is an implementation of an operation that specifies the algorithm or procedure.
Multiplicity
A multiplicity is a specification of the range of allowable cardinality values. It can be an explicit value, a range of values, or an expression that resolves to one or more values.
Model
A model is semantically complete abstraction of a system from a particular viewpoint.
>>> N <<<
Name
A name is a string that is defined within a namespace and is used to identify a model element.
Namespace
A namespace is a part of the model in which names are defined and used, where each name has a unique meaning.
Navigation Pane
The Navigation pane is located in the top left corner of the Poseidon work area and displays model elements according to pre-determined schemas which can be selected from a dropdown menu.
Note
A node is a physical object that exists at runtime and represents a computational resource that executes components. It usually has at least a memory and often processing capability. Nodes can include, but are not limited to, computing devices, human resources, or mechanical processing resources.
>>> O <<<
Object
An object is a discrete entity with a well-defined boundary and identity that encapsulates state and behavior, an instance of a class.
Operation
An operation is the specification of a transformation on the state of an object or a query that returns a value to the caller of the operation.
Overview Pane
The Overview pane is located in the bottom left-hand corner of the Poseidon application and helps the user keep the big picture in mind.
>>> P <<<
Package
A package, like a file directory, is a general way to put like things together to provide organization. Packages may be nested within other packages.
Parameter
A parameter is the placeholder for an argument that can be changed, passed or returned.
Project
A project is saved as a zipped .zuml file and contains all information regarding the model, both textual and graphical.
>>> R <<<
Relationship
A relationship is reified semantic connection among model elements. Types of relationships include association, generalization, and dependency.
Role
A role is a named slot within an object structure that represents the behavior of an element as it participates in a given context (in contrast to the inherent qualitites of the element).
>>> S <<<
Specialization
A specialization produces a more specific description of a model element by adding children. A child element is the specialization of a parent element.
Stereotype
A stereotype characterizes a type of element without specifying its implementation and assists in teh creation of a new model element that is derived from an existing model element.
>>> T <<<
Type
A type is a declared classifier that the value of an attribute, parameter, or variable must hold. The actual value must be an instance of that type or one of its descendants.
>>> U <<<
UML
Unified Modeling Language - you find a very appealing illustration of UML and its components, as well as many other terms and definitions in different languages in Wikipedia - The Free Encyclopedia
