Pons Asinorum

Pons Asinorum (i.e. Bridge of Asses), the fifth proposition in the 1st book of Euclid, so called for the difficulty many a tyro has in mastering it.

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

Poniatowski, Prince Joseph * Ponsonby, Sir Frederick Cavendish
Pomona
Pompadour, Marquise de
Pompeii
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