P.p. Definition

abbreviation
Parcel post.
American Heritage
Past participle.
American Heritage
Per procurationem (by proxy)
American Heritage
Postpaid.
American Heritage

Post, meaning after.

Wiktionary
letter

The sixteenth letter of the English alphabet, called pee and written in the Latin script.

Wiktionary
numeral

The ordinal number sixteenth, derived from this letter of the English alphabet, called pee and written in the Latin script.

Wiktionary
symbol

(sports) Postponed fixture.

Wiktionary