Posse
A Law Dictionary and Glossary · George C. Kinney · 1893
A Law Dictionary and Glossary
I, To be able; to be possible; possibility; ability; power; a force; a number of persons summoned to assist a sheriff in the execution of process. Posse comitatus: the power or force of the county; the entire population of a county above the age of fifteen, which a sheriff may summon to his assistance in certain cases.
In old English law
Posse balliviiB: the power of the bailiwick.