- Document Type Definition, a method for specifying valid characteristics (elements and attributes) for an XML document.
- Interactive Development Environment
- A namespace is a way of defining a context for identifiers, so that identifiers from different contexts might have identical names, but still be distinguished by their namespace context. For our purposes, namespaces are used to delegate authority for defining what will appear where in PDS4 labels. The contents of the pds4 namespace is defined by the PDS master schema. The contents of a discipline namespace, like sbn (for Small Bodies) are defined by a local dictionary schema created and maintained by a discipline specialist. Namespaces are identified by URIs, and are usually resolved to physical references by an XML Catalog file.
- Uniform Resource Identifier. A globally unique identifier for some entity - like a local dictionary, a book, a website, etc. Here's a Wikipedia article that does an excellent job of describing what a URI is and does: wikipedia:Uniform_resource_identifier
- A character encoding scheme for representing Unicode Character code points with the minimum necessary bytes. The UTF-8 encoding of 7-bit printable ASCII characters is identical to the ASCII encoding.
- XML Catalog
An XML Catalog file is an XML file written to conform with the XML Catalog standard. This standard provides a uniform way to define a translation table to take logical links, like URIs, that appear in XML files, and convert them to physical references - that is, references to physical files that can be opened and used for things like validation.
- XML-aware editor
- An XML-aware editor has programmed-in behavior to assist users in creating and editing XML documents. This usually includes things like auto-indenting, automatically adding closing tags for each opening tag you type, and such. Many also provide additional capabilities, like being able to read coded information in DTDs or Schema files and being able to suggest valid attributes and values for auto-completion.