The Interactive Glossary: Defining the Net
PDF

An acronym for Portable Document Format, PDF is a file type created by Adobe Systems, Inc. that allows fully formatted, high-resolution, PostScript documents to be easily transmitted across the Internet and viewed on any computer that has Adobe Acrobat Reader software (a proprietary viewer is available for free at the Adobe site).
Corporations that have invested in brand name identification use PDF to display the original look of their logos and advertising. Publishers can create a high-quality brochure and then "publish" it as is, without converting it to HTML. Anyone interested in presenting documents with the highest possible resolution or a complex layout might choose to use PDF.
PDF files can be distributed via e-mail, web pages, CD-ROMs, online services and LANs. They can also contain hypertext, QuickTime movies, and sound clips.