fief

a region of activity, knowledge, or influence <the logistics of the relief effort is the director's fief> Synonyms area, arena, bailiwick, barony, business, circle, demesne, department, discipline, domain, element, field, fiefdom, firmament, front, game, kingdom, line, precinct, province, realm, specialty, sphere, terrain, walkRelated Words frontier; study, subject; territory, turf; occupation, profession, pursuit, racket, vocation; ambit, amplitude, breadth, compass, confine, dimension(s), extent, ken, reach, scope, sweep, width; subfield, subspecialty