\Plan"i*sphere\, n. [Plani- + sphere: cf. F.
planisph[`e]re. See {Plain}, and {Sphere}.]
The representation of the circles of the sphere upon a plane;
especially, a representation of the celestial sphere upon a
plane with adjustable circles, or other appendages, for
showing the position of the heavens, the time of rising and
setting of stars, etc., for any given date or hour.