Definition of "Sphere" :

noun: any spherically shaped artifact

noun: a particular aspect of life or activity

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

noun: the geographical area in which one nation is very influential

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

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

noun: a particular environment or walk of life

"His social sphere is limited."