sphere

Definitions

• (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 .
• A spherical physical object; a globe or ball.
• (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.
• (historical) Any of the concentric hollow transparent globes formerly believed to rotate around the Earth, and which carried the heavenly 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).
• (mythology) An area of activity for a planet; or by extension, an area of influence for a god, hero etc.
• (figuratively) The region in which something or someone is active; one's province, domain.
• (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 .
• (logic) The extension of a general conception, or the totality of the individuals or species to which it may be applied.