Glossary

Term Definition
Abstract Data Type (ADT) A mathematical formalism for defining the characteristics of a certain data type, without revealing the underlying model, let alone any concrete implementation in a computer program. An ADT defines exactly what is required of an implementation, and, by omission, also what is not required.
Attribute An attribute provides more information about an element such as classification level, unique reference identifiers, or formatting information.
CGM (Computer Graphics Metafile) CGM is one of the CALS standard formats for representing 2-D technical illustrations. CGM is an object-oriented graphic format.
Data Marshalling The process of linearizing a data structure into a sequence of bytes in a certain, previously agreed-upon way, so that one process can pass its internal data structure to another process, which will then be able to build an equivalent data structure.
DOM (Document Object Model) The DOM is a standardized Application Programming Interface (API) which is used as a mechanism for accessing the tree structure of XML and HTML documents. The DOM provides a standardized, object-oriented application development model for accessing the trees of Web documents. Some parts of the DOM provide scripting interfaces for accessing HTML and XML documents from within a browser. Specific sections of DOM provide language-specific bindings (Java, JavaScript, C++).
DSSSL (Document Style Semantics and Specification Language) This draft international standard (DIS 10179) applies to the specification of processing information for SGML documents. DSSSL became an international standard in 1995. DSSSL (Document Style Semantics and Specification Language. DSSSL is a very powerful document transformation and formatting language that never really caught on -- largely due to its complexity. One of the goals behind XSL is to provide DSSSL-like semantics without using DSSSL's complex syntax. (Instead, an XML-based syntax is used.)
DTD (Document Type Definition) A DTD is the formal definition of the elements, structures, and rules for marking up a given type of SGML document. You can store a DTD at the beginning of the document or externally in a separate file.
EDI (Electronic Data Interchange) This is a set of computer interchange standards for business documents such as invoices, bills, and purchase orders.
element An element is a piece of data within a document that may contain either text or other subelements such as a paragraph, a chapter, and so on.
Element Declaration A statement in the DTD defining an element and declaring the order in which it may appear in the document and what other elements it may include.
Entity An entity is a self-contained piece of data that can be referenced as a unit. You can refer to an entity by a symbolic name in the DTD or the document. An entity can be a string of characters, a character that cannot be entered on a keyboard (such as a special symbol), a separate text file, or a separate graphic file.
Entity Declaration A statement in the DTD or document that assigns an SGML name to an entity so you can reference it.
Markup Markup is anything added to the content of the document that describes the text.
Parser A parser is a specialized software program that recognizes SGML markup in a document. A parser that reads a DTD and checks and reports on markup errors is a validating SGML parser. A parser can be built into an SGML editor to prevent incorrect tagging and to check whether a document contains all the required elements.
XML Media Type A potentially rich data type that contains Strings and Identifiers, partly ordered in a sequence, partly hierarchical, partly in an unordered database-like keyword/value system.