PDF is the Portable Document Format in computing.

Pi Delta Phi (ΠΔΦ) is the National French Honor Society for undergraduate and graduate students at accredited public and private colleges and universities in the United States. The society was admitted to membership in the Association of College Honor Societies in 1967.

The Portable Document Format (PDF) is a file format used to present documents in a manner independent of application software, hardware, and operating systems. Each PDF file encapsulates a complete description of a fixed-layout flat document, including the text, fonts, graphics, and other information needed to display it. In 1991, Adobe Systems' co-founder John Warnock outlined a system called "Camelot" that developed into PDF.