posse comitatus

noun

1. Historical
   in full posse comitatus
   1. the body of men required, upon being summoned, to assist the sheriff in keeping the peace, pursuing felons, etc.
   2. a band of men, usually armed, so summoned
2. any body of persons armed with legal authority
3. ☆
   1. in the Old West, a group assembled to hunt for criminal fugitives
   2. a search party
4. Slang
   1. a gang, esp. one engaged in selling drugs
   2. any group of people, as of a person's friends and associates