sphere

1 a more or less round body or mass <this sphere that we live on is just a tiny speck in the universe> Synonyms globe, orb, {h,1}ballRelated Words bead, globule; egg, ellipse, loop, oval, spheroid; circle, ring, rondure, round; chunk, clump, gob, hunk, lump, nugget, wadNear Antonyms block, cube, rectangle, square

2 a region of activity, knowledge, or influence <higher mathematics is a little outside my sphere> Synonyms area, arena, bailiwick, barony, business, circle, demesne, department, discipline, domain, element, fief, fiefdom, firmament, front, game, kingdom, line, precinct, province, realm, specialty, field, 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

3 a ball-shaped gaseous celestial body that shines by its own light <perhaps there is indeed life on planets circling spheres in galaxies far, far away> Synonyms luminary, star, sunRelated Words cluster, constellation, galaxy; binary star, brown dwarf, dwarf, fixed star, gasser, giant star, lodestar (also loadstar), neutron star, nova, pulsar, quasar, red dwarf, red giant, red star, subdwarf, supercluster, supergiant, supernova, variable, variable star, white dwarf