sphere

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. Mathematics A three-dimensional surface, all points of which are equidistant from a fixed point.
2. n. A spherical object or figure.
3. n. A celestial body, such as a planet or star.
4. n. The sky, appearing as a hemisphere to an observer: the sphere of the heavens.
5. n. Any of a series of concentric, transparent, revolving globes that together were once thought to contain the moon, sun, planets, and stars.
6. n. The extent of a person's knowledge, interests, or social position.
7. n. An area of power, control, or influence; domain. See Synonyms at field.
8. v. To form into a sphere.
9. v. To put in or within a sphere.
10. v. To surround or encompass.

Century Dictionary and Cyclopedia

1. n. In geometry, a solid figure generated by the revolution of a semicircle about its diameter. This is substantially Euclid's definition. The modern definition is a quadric surface having contact with the absolute throughout a conic, and therefore everywhere equidistant from a center. The surface of a sphere is 4πR, where R is the radius; its volume is .
2. n. Hence A rounded body, approximately spherical; a ball; a globe.
3. n. An orbicular body representing the earth or the apparent heavens, or illustrating their astronomical relations.
4. n. Hence The visible supernal region; the upper air; the heavens; the sky.
5. n. One of the supposed concentric and eccentric revolving rigid and transparent shells called crystalline, in which, according to the old astronomers (following Eudoxus), the stars, sun, moon, and planets were severally set, and by which they were carried in such a manner as to produce their apparent motions. The term is now generally restricted to the sphere of the fixed stars, and is recognized as a convenient fiction. It is also loosely applied to the planets themselves.
6. n. Hence An orbicular field or course of movement; an orbit, as that of a heavenly body or of the eye; a circuit.
7. n. Place or scene of action; the space within which movement is made or operations are carried on; a circumscribed region of action: as, the sphere of a mission; the spheres (fuller, spheres of influence) of the different European powers and trading companies in Africa.
8. n. Position or rank in society; position or class with reference to social distinctions.
9. n. Circuit or radius, as of knowledge, influence, or activity; definite or circumscribed range; determinate limit of any mental or physical course: as, the sphere of diplomacy.
10. n. More generally, a sphere (discovered in 1884 by the Italian mathematician Intrigila) belonging to any tetrahedron, and passing thruogh the four feet of the perpendiculars from the summits upon the opposite faces, and consequently also through the mid-points of the lines from the summits to the center of the hyperboloid of which these perpendiculars are generator, and through the orthogonal projections of these points upon the opposite faces.
11. n. = Syn. 1–3. Orb, Ball, etc. See globe.
12. To make into a sphere; make spherical; round, or round out; fill out completely.
13. To place in a sphere or among the spheres: ensphere.
14. To inclose as in a sphere or orbit; encircle; engirdle.
15. To pass or send as in a sphere or orbit; circulate.
16. n. A spherical sponge-spicule, a modified form of monaxial type.

Wiktionary

1. v. transitive To place in a sphere, or among the spheres; to ensphere.
2. v. transitive To make round or spherical; to perfect.

GNU Webster's 1913

1. n. (Geom.) A body or space contained under a single surface, which in every part is equally distant from a point within called its center.
2. n. Hence, any globe or globular body, especially a celestial one, as the sun, a planet, or the earth.
3. n. The apparent surface of the heavens, which is assumed to be spherical and everywhere equally distant, in which the heavenly bodies appear to have their places, and on which the various astronomical circles, as of right ascension and declination, the equator, ecliptic, etc., are conceived to be drawn; an ideal geometrical sphere, with the astronomical and geographical circles in their proper positions on it.
4. n. In ancient astronomy, one of the concentric and eccentric revolving spherical transparent shells in which the stars, sun, planets, and moon were supposed to be set, and by which they were carried, in such a manner as to produce their apparent motions.
5. n. (Logic) The extension of a general conception, or the totality of the individuals or species to which it may be applied.
6. n. Circuit or range of action, knowledge, or influence; compass; province; employment; place of existence.
7. n. Rank; order of society; social positions.
8. n. rare An orbit, as of a star; a socket.
9. v. To place in a sphere, or among the spheres; to insphere.
10. v. To form into roundness; to make spherical, or spheral; to perfect.

WordNet 3.0

1. n. the geographical area in which one nation is very influential
2. n. any spherically shaped artifact
3. n. a solid figure bounded by a spherical surface (including the space it encloses)
4. n. a three-dimensional closed surface such that every point on the surface is equidistant from the center
5. n. a particular environment or walk of life
6. n. the apparent surface of the imaginary sphere on which celestial bodies appear to be projected
7. n. a particular aspect of life or activity