Portable Document Format, a set of formats and open standards maintained by the International Organization for Standardization for producing and sharing electronic documents originally developed by Adobe Systems. The original page description format has been elaborated over successive versions to enable the embedding of such complex objects as image, audio, and moving image files, hyperlinks, embedded XML metadata, and updatable forms. Specification for various versions and profiles of the format are now maintained by the International Standards Organization. http://www.adobe.com/uk/products/acrobat/adobepdf.html;
Definition by https://www.dpconline.org/handbook/glossary
