Pontifex Maximus

Pontifex Maximus, the chief of the college of priests in ancient Rome, the officiating priests being called Flamens.

Definition taken from The Nuttall Encyclopædia, edited by the Reverend James Wood (1907)

Pontefract * Pontifical
[wait for the fun]
Pompey, Cneius
Pompey's Pillar
Ponce de Leon
Poncho
Pondicherry
Pondos
Poniatowski, Prince Joseph
Pons Asinorum
Ponsonby, Sir Frederick Cavendish
Pontefract
Pontifex Maximus
Pontifical
Pontine Marshes
Pontus
Poole
Poole, Matthew
Poona
Poor Richard
Pope
Pope, Alexander
Popish Plot