The Portable Document Format (PDF or pdf) is a file format to present documents, including text formatting and images, in a manner independent of application software, hardware, and operating systems. It is the most common file format for publishing role-playing games and related products as e-books.
PDF files may contain a variety of content besides flat text and graphics including logical structuring elements, interactive elements such as annotations and form-fields, layers, rich media (including video content) and three dimensional objects using U3D or PRC, and various other data formats.
It was developed by Adobe in the 1990s and has become so widespread partly because Adobe released the specification free of charge on first release, and then released it as an open standard in 2008.
- PDF at Wikipedia, the free encyclopedia.