sphere

Noun

• the apparent surface of the imaginary sphere on which celestial bodies appear to be projected

• a three-dimensional closed surface such that every point on the surface is equidistant from the center

• a solid figure bounded by a spherical surface (including the space it encloses)

• a particular aspect of life or activity
  • he was helpless in an important sector of his life
    

• the geographical area in which one nation is very influential

• any spherically shaped artifact

• a particular environment or walk of life
  • his social sphere is limited
    
  • it was a closed area of employment
    
  • he's out of my orbit
    

Related words

• Synonyms: 
  celestial sphere , empyrean , firmament , heavens , vault of heaven , welkin , sector , sphere of influence , domain , area , orbit , field , arena