Definitionen
1.NounAny representation (map projection) of part of a sphere on a plane surface.
2.NounA map constructed by stereographic projection, as described in Ptolemy's treatise Planisphaerium and later used in planispheric astrolabes
3.NounA map of the whole world, especially those from the 16th–17th century
4.NounAny of several charts of the celestial sphere having an overlay or window that may be adjusted to show the stars visible at a particular time, or from a particular place.