Poseidon

Poseidon, in the Greek mythology the god of the sea, a son of Kronos and Rhea, and brother of Zeus, Pluto, Hera, Hestia, and Demeter; had his home in the sea depths, on the surface of which he appeared with a long beard, seated in a chariot drawn by brazen-hoofed horses with golden manes, and wielding a trident, which was the symbol of his power, exercised in production of earthquake and storms. See Pluto.

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

Portugal * Posen
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Porteus, Beilby
Portia
Portland
Portland, Isle of
Portland Vase
Porto Rico
Portobello
Portsmouth
Portsmouth
Portugal
Poseidon
Posen
Posidonius
Positivism
Posse Comitatus
Post Restante
Potemkin
Potomac River
Potosi
Potsdam
Pott, August Friedrich