posse
Pronunciation: /ˈpɒsi/
noun
- 1US historical a body of men summoned by a sheriff to enforce the law.
- (also posse comitatus /ˌkɒmɪˈteɪtəs/) British historical the body of men above the age of fifteen in a county (excluding peers, the clergy, or the infirm), whom the sheriff could summon to repress a riot or for other purposes.[comitatus from medieval Latin, 'of the county']

Origin:
mid 17th century: from medieval Latin, literally 'power', from Latin posse 'be able'