2 Answers

Definition for pdf documents:
Web definitions:
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Definition:
Portable Document Format or PDF is a file format created by Adobe Systems, Inc. PDF uses the PostScript printer description language and is highly portable across computer platforms. PDF documents have a .pdf file extension (myfile.pdf)

A de facto standard file format, use PDF to:

Share files with others who don't have the same software
Share files with others who use a different platform (Mac, Windows, Linux, etc.)
Share files that will look the same (layout, fonts) on multiple computer systems
Share files that can be protected from unauthorized viewing, printing, copying, or editing
Publish electronic documents, ebooks, etc.
Print files to many different types of printers, and all look essentially the same
Create files with annotations, hyperlinks, and bookmarks that can be shared via email and on the Web
Create interactive forms that can be shared via email and the Web
Create files that are more efficient than PostScript or native file formats typically used in commercial printing
PDF documents are created with Adobe Acrobat Distiller or other PDF creation apps. Some desktop publishing apps can create PDF files from within the program, usually with the assistance of helper programs. Adobe Acrobat Reader is the main software for opening and viewing PDF documents.

Working with PDF

If you have Distiller, here's how to save a PostScript file as a PDF.
How to Get Text or Images Out of a PDF File describes several ways to extract text and graphics for use in other applications.
Watch a video on using Adobe Acrobat to Extract Text and Images from a PDF.
Pronunciation: Each letter in PDF is pronounced separately: P*D*F
Also Known As: portable document format | Acrobat files
Examples:
Some designers generate PDF documents from their page layout applications and send the PDF documents to customers so that they can view and proof the design without having the same software and fonts installed. Increasingly, PDF documents are used in place of PostScript or native file formats for having material commercially printed.
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