PE (ף, p). The seventeenth letter of the Heb. alphabet. It also was used for the number 80. It introduces the seventeenth part of Psalm 119 (KJV), every v. of which begins with this letter.

International Standard Bible Encyclopedia (1915)

"p": The 17th letter of the Hebrew alphabet; transliterated in this Encyclopedia as "p" with daghesh and "ph" (equals f) without. It came also to be used for the number 80. For name, etc., see Alphabet.