Emily Dickinson Lexicon

POSSE-COMITATUS, n. [Posse comitatus.]

1. In law, the power of the county, or the citizens, who are summoned to assist an officer in suppressing a riot, or executing any legal precept which is forcibly opposed. The word comitatus is often omitted, and posse alone is used in the same sense. – Blackstone.
2. In low language, a number or crowd of people; a rabble.