[ 'planɪsfɪə ]
■ noun a map formed by the projection of a sphere, especially a star map that can be adjusted to show the constellations at a specific time and place.
Derivatives
planispheric -'sfɛrɪk adjective
Origin
ME planisperie , from med. L. planisphaerium , from L. planus 'level' + sphaera 'sphere'.