A wick, in olden times, was a village, from the Latin, vicus, village.
It survives now chiefly in place names, often as with, as in Warwick, Greenwich, Norwich. And the bailie, whom we now call bailiff, was the administrative officer. Thus a bailiwick was actually the district over which a bailiff had jurisdiction.
We use the term figuratively now to mean also any place that one regards as one’s own.