Posse Comitatus
Black's Law Dictionary · Henry Campbell Black, M.A. · 1910
Black's Law Dictionary
Lat. The power or force of the county. The entire pbpulation of a county above the age of fifteen, which a sheriff may summon to his assistance in certain cases; as to aid him in keeping the peace, in pursuing and arresting felons, etc.
1 Bl. Comm. 343. See Com. v. Martin, 7 Pa. Dist R. 224.