constabulary (n.)

1630s, "district under a constable," from Medieval Latin constabularia, from constabulus, Latinized form of Old French conestable (see constable).

Meaning "organized body of peace officers in a district" is from 1837. Earlier (mid-15c.) it was an adjective, "pertaining to a constable."

The earlier noun was constablery (mid-14c., constablerie), "office of a constable;" early 15c. as "district or headquarters of a constable," from Old French conestablerie.