n. 1. Mathematics A three-dimensional surface, all points of which are equidistant from a fixed point. 2. A spherical object or figure. 3. A celestial body, such as a planet or star. 4. The sky, appearing as a hemisphere to an observer: the sphere of the heavens. 5. Any of a series of concentric, transparent, revolving globes that together were once thought to contain the moon, sun, planets, and stars. 6. a. A range or extent of knowledge, interest, or activity: a problem that falls within the sphere of biophysics. See Synonyms at field. b. A social level or part of society or group: knew few people beyond his partner's sphere. c. A range of power or influence: within the sphere of the empire. tr.v. sphered, spher·ing, spheres 1. To form into a sphere. 2. To put in or within a sphere. [Middle English spere, from Old French espere, from Latin sphaera, from Greek sphaira.] sphe·rici·ty (sfîr-ĭsĭ-tē) n. |
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