firmament

1 the expanse of air surrounding the earth the stars in the firmament twinkled ever so brightly Synonyms blue, sky, heaven(s), high, welkinRelated Words midair; horizon, skyline

2 a region of activity, knowledge, or influence a major figure in the classical music firmament Synonyms area, arena, bailiwick, barony, business, circle, demesne, department, discipline, domain, element, fief, fiefdom, field, 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