realm

1 a region of activity, knowledge, or influence medieval history is really Professor Clinton's realm, so I'll let her answer your question Synonyms area, arena, bailiwick, barony, business, circle, demesne, department, discipline, domain, element, fief, fiefdom, firmament, front, game, kingdom, line, precinct, province, field, 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

2 an area over which activity, capacity, or influence extends a medical breakthrough that is within the realm of possibility Synonyms ambit, amplitude, breadth, compass, confines, dimension(s), extent, reach, range, scope, sweep, widthRelated Words gamut, spectrum, spread; bailiwick, circle, demesne, department, discipline, domain, element, fief, fiefdom, field, province, region, specialty, sphere, terrain; frontier; horizon, panorama