For the purposes of this document, the following abbreviated terms apply:
| ASCII | American Standard Code for Information Interchange |
| CSI | code space identifier |
| DTD | document type definition |
| HTML | HyperText Markup Language |
| IANA | Internet Assigned Numbers Authority |
| IG | identification guide |
| MIME | Multipurpose Internet Mail Extensions |
| OTD | open technical dictionary |
| UML | Unified Modeling Language |
| URI | uniform resource identifier |
| URL | uniform resource locator |
| W3C | World Wide Web Consortium |
| XML | Extensible Markup Language |