1 Answer

PP, pp, Pp, or Pp may refer to:
Places

Phi Phi Islands, in Thailand
Computers and computing[edit]

p&p, plug and play, a type of peripheral device used in computing
PP-format, a Met Office proprietary file format for distributing climate data
Politics

People's Party (Spain) (Partido Popular)
Progressive Party (Brazil) (Partido Progressista)
Progressive Party (Iceland)
Religion

Papa (Latin for Pope), when written "PP."
parish priest, written "P.P."
Science, medicine and engineering[edit]

Length between perpendiculars ("pp" or "p/p"), a nautical term
Vitamin PP also known as Nicotinamide
pancreatic polypeptide, a substance produced by the body during the process of digestion
PP cell, cell producing pancreatic polypeptide
peak to peak (p–p), a way of measuring the amplitude of a signal
percentage point
per protocol population in clinical trials
Piecewise polynomial, see spline (mathematics)
polypropylene, a very common plastic polymer
PP (complexity), probabilistic polynomial time complexity class
PP email system.
P–P plot
process performance index (Pp), a tool used in statistical calculations
proton–proton chain reaction, in nuclear physics
planned parenthood
Other

As either pp or p.p., standing for per procurationem, from the Latin by agency - used when signing on behalf of someone else
Pages, from Latin paginae, see acronyms
Past participle, a form of a verb which is used in a sentence to modify a noun or noun phrase, often represented by "pp." in dictionaries
'Pianissimo' a term of musical dynamics
Walther PP, a semi-automatic pistol.

http://en.wikipedia.org/wiki/PP