PDF

This term is an abbreviation for Portable Document Format. In professional and technical communication, it is used both as a noun to describe the file itself and as a shorthand for the specific standard of document presentation.

Because it is a technical specification, it is typically treated as a countable noun when referring to individual files. It is common to see it used in phrases like "send a PDF" or "save as a PDF," where the article "a" is used despite the word starting with a consonant letter but a vowel sound (pee-dee-eff).