Merriam-Webster Collegiate Dictionary - sphere

 I. noun  Etymology: Middle English spere globe, celestial ~, from Anglo-French espere, from Latin sphaera, from Greek sphaira, literally, ball; perhaps akin to Greek spairein to quiver — more at spurn  Date: 14th century  1.  a.  (1) the apparent surface of the heavens of which half forms the dome of the visible sky  (2) any of the concentric and eccentric revolving spherical transparent shells in which according to ancient astronomy stars, sun, planets, and moon are set  b. a globe depicting such a ~; broadly globe a  2.  a. a globular body ; ball  b. planet, star  c.  (1) a solid that is bounded by a surface consisting of all points at a given distance from a point constituting its center — see volume table  (2) the bounding surface of a ~  3. natural, normal, or proper place; especially social order or rank not in the same ~ as his moneyed friends  4.  a. obsolete orbit  b. an area or range over or within which someone or something acts, exists, or has influence or significance the public ~  • spheric adjective, archaic  • sphericity noun  II. transitive verb  (~d; sphering)  Date: 1602  1. to place in a ~ or among the ~s ; en~  2. to form into a ~