Sphere

noun
1.
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.

2.
any rounded body approximately of this form; a globular mass, shell, etc.
3.
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.

4.
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.
5.
a particular social world, stratum of society, or walk of life:
His social sphere is small.
6.
a field of something specified:
a sphere of knowledge.
verb (used with object), sphered, sphering.
7.
to enclose in or as if in a sphere.
8.
to form into a sphere.
9.
to place among the heavenly spheres.
1.
a combining form of sphere (planisphere); having a special use in the names of the layers of gases and the like surrounding the earth and other celestial bodies (ionosphere).
noun
1.
(maths)

a three-dimensional closed surface such that every point on the surface is equidistant from a given point, the centre
the solid figure bounded by this surface or the space enclosed by it. Equation: (x–a)² + (y–b)² + (z–c)² = r², where r is the radius and (a, b, c) are the coordinates of the centre; surface area: 4πr²; volume: 4πr³/3

2.
any object having approximately this shape; globe
3.
the night sky considered as a vaulted roof; firmament
4.
any heavenly object such as a planet, natural satellite, or star
5.
(in the Ptolemaic or Copernican systems of astronomy) one of a series of revolving hollow globes, arranged concentrically, on whose transparent surfaces the sun (or in the Copernican system the earth), the moon, the planets, and fixed stars were thought to be set, revolving around the earth (or in the Copernican system the sun)
6.
particular field of activity; environment: that’s out of my sphere
7.
a social class or stratum of society
verb (transitive) (mainly poetic)
8.
to surround or encircle
9.
to place aloft or in the heavens
combining form
1.
having the shape or form of a sphere: bathysphere
2.
indicating a spherelike enveloping mass: atmosphere

sphere (sfēr)
n.
A ball-shaped or a globular body.
spher’al (sfēr’əl) adj.
sphere
(sfîr)
A three-dimensional geometric surface having all of its points the same distance from a given point.