Posse Comitatus

Posse Comitatus, a Latin expression, signifies the whole coercive power of a county called out in the case of a riot, and embraces all males over 15 except peers, ecclesiastics, and infirm persons. These may be summoned by the sheriff to assist in maintaining the public peace, enforcing a writ, or capturing a felon; but usually the constabulary is sufficient for these duties.

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

Positivism * Post Restante
Portland Vase
Porto Rico
Portobello
Portsmouth
Portsmouth
Portugal
Poseidon
Posen
Posidonius
Positivism
Posse Comitatus
Post Restante
Potemkin
Potomac River
Potosi
Potsdam
Pott, August Friedrich
Potter, John
Potter, Paul
Potteries, The
Pot-wallopers