Short for Portable Document Format, an Adobe technology that allows people to share documents that preserve their original appearance, including embedding the specific fonts used in the document. PDFs can also contain interactive elements such as web and email links and form fields.
Though other applications can create PDFs, the primary application for creating and modifying PDFs is Adobe Acrobat. Portable Document Format has gained in popularity and credibility as many professional printing houses request high resolution PDFs as the default format.
Some type designers and type foundries have reservations about the security PDFs as it is still possible for dedicated hackers to pull font outlines from a PDF. For this reason some foundries’ EULAs disallow embedding their fonts in PDFs.