Bailiwick \BAY-luh-wik\ noun
1. A person's specific area of knowledge, authority, interest, skill, or work.
2. The office or district of a bailiff.
Bailiwick comes from Middle English baillifwick, from bailif, "bailiff" (ultimately from Latin bajulus, "porter, carrier") + wik, "town", from Old English wic, from Latin vicus, "village".