Geometry .

a solid geometric figure generated by the revolution of a semicircle about its diameter; a round body whose surface is at all points equidistant from the center. Equation

x 2 y 2 z 2 r 2

the surface of such a figure; a spherical surface.

any rounded body approximately of this form; a globular mass, shell, etc.

Astronomy .

a planet or star; heavenly body.

celestial sphere.

any of the transparent, concentric, spherical shells, or layers, in which, according to ancient belief, the planets, stars, and other heavenly bodies were set.

the place or environment within which a person or thing exists; a field of activity or operation

to be out of one's professional sphere.

a particular social world, stratum of society, or walk of life

His social sphere is small.

a field of something specified

a sphere of knowledge.

to enclose in or as if in a sphere.

to form into a sphere.

to place among the heavenly spheres.

noun

apple * , ball , big blue marble , circle , earth , globe , globule , orb , pellet , pill , planet , rondure , round , bailiwick , capacity , champaign , class , compass , demesne , department , dominion , employment , field , function , ground , jungle , jurisdiction , level , neck of the woods , orbit , pale , position , precinct , province , range , rank , realm , scope , station , stomping ground , stratum , terrain , territory , turf * , walk of life , zone , ambit , extension , extent , purview , reach , sweep , swing , area , arena , beat , business , circuit , domain , influence , milieu , order , orrery , preserve , region , sky , sphericity , spheroid , spheroidicity , star , theater