Button: An area of the display screen on which the user can 'click' with a pointing device. A button is the physical manifestation of a link.
Cognitive map: A model or schema in the human mind of a place or an area, in this case a hypermedia structure.
Card: In some hypermedia systems, especially those based on a note cards metaphor, the nodes are called cards.
Context: The setting in which an item of information appears.
Hypermedia: A visual, interactive and non-linear medium for communica-tion, which is based on a human-computer interaction paradigm where the user can browse through a database using point and click interaction techniques.
Hypermedia structure: The database of a hypermedia system. The most common data model for representing information is nodes of information connected with links in a network structure.
Hypermedia system: A hypermedia system contains of a database and a graphical user interface to the database. The database usually consists of nodes connected with links in a network structure. The interface usually reflects the network structure of the database. Traversing the network by following links is the basic operation for finding information in a hypermedia system. We will use the terms hypermedia network and hypermedia structure, to denote the contents and structure of the database.
Hypermedia tool: A hypermedia tool is a high-level development environment for implementing hypermedia systems.
Landmark knowledge: Knowledge of a central points of reference.
Lexivisual presentation: A set of principles and techniques for how to present information (with text and pictures) in printed media. Central principles are: focus on the primary message, and present detailed information in the context of the whole. This can reduce the risk of loosing track of what one is reading. Often graphical techniques like zoom-boxes, miniaturized maps, and speech balloons are used. Lexivisual presentation is used in, for instance, modern encyclopedias, comic books and instruction manuals.
Link: Links connect the nodes of a hypermedia network. Sometimes button is used in a meaning equivalent to link.
Navigation: Traversing the hypermedia structure with the goal of finding a particular information item (node). In order to navigate successfully one must be oriented.
Node: Nodes contain information in a hypermedia system. Nodes are sometimes called cards.
Orientation: Knowing where in a hypermedia structure one currently is, and how that part is related to other parts in the structure. In order to orient oneself it is necessary to have an overall knowledge of the structure and the information contained therein.
Orientational information: Information necessary to orient oneself in a hypermedia system.
Overview: Knowledge about the information contained in a hypermedia system and its structure on an overall level.
Survey knowledge: Overall knowledge of a hypermedia system. Similar to overview.
Tunnel vision: Lack of a high-level view of a hypermedia system. Tunnel vision is caused by, among other things, information being presented in small fragments not related to their context. The opposite to world vision.
Visual communication: Communication by presenting information in a visual form. There exist a variety of ways to present information visually, like gestures, body languages, video, and TV. Here, focus is on the presentation of text, pictures, diagrams, photos, et cetera, integrated on a computer display. The term visual presentation is used to refer to the actual presentation of information.
World vision: High-level, overall view of a hypermedia system. Similar to overview. The opposite to tunnel vision.