sphere

  1. Noun.  (mathematics) A regular three-dimensional object in which every cross-section is a circle; the figure described by the revolution of a circle about its diameter (defdate, from 14th c.) .
  2. Noun.  A spherical physical object; a globe or ball. (defdate, from 14th c.) .
  3. Noun.  (context, astronomy) The apparent outer limit of space; the edge of the heavens, imagined as a hollow globe within which celestial bodies appear to be embedded. (defdate, from 14th c.) .
  4. Noun.  (historical, astronomy) Any of the concentric hollow transparent globes formerly believed to rotate around the Earth, and which carried the heavenly bodies; there were originally believed to be eight, and later nine and ten; friction between them was thought to cause a harmonious sound (the ''music of the spheres''). (defdate, from 14th c.) .
  5. Noun.  (mythology) An area of activity for a planet; or by extension, an area of influence for a god, hero etc. (defdate, from 14th c.) .
  6. Noun.  (figuratively) The region in which something or someone is active; one's province, domain. (defdate, from 17th c.) .
  7. Noun.  (geometry) The set of all points in three-dimensional Euclidean space (or (n) -dimensional space, in topology) that are a fixed distance from a fixed point (defdate, from 20th c.) .

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This entry was last updated on RefTopia from its source on 3/20/2012.