- a map or chart that is the projection on a plane of all or part of a sphere
- a projection on a plane of the celestial sphere, usually with the N or S celestial pole as the center
Origin of planisphereMedieval Latin planisphaerium: see plani- and amp; sphere
- A representation of a sphere or part of a sphere on a plane surface.
- Astronomy A polar projection of half or more of the celestial sphere on a chart equipped with an adjustable overlay to show the stars visible at a particular time and place.
- pla′ni·spher′ic , pla′ni·spher′i·cal