planisphere n.

*pelə-, Proto-Indo-European root meaning "flat; to spread."

It forms all or part of: airplane; dysplasia; ectoplasm; effleurage; esplanade; explain; explanation; feldspar; field; flaneur; floor; llano; palm (n.1) "flat of the hand;" palm (n.2) "tropical tree;" palmy; piano; pianoforte; plain; plan; planar; Planaria; plane (n.1) "flat surface;" plane (n.3) "tool for smoothing surfaces;" plane (v.2) "soar, glide on motionless wings;" planet; plani-; planisphere; plano-; -plasia; plasma; plasmid; plasm; -plasm; -plast; plaster; plastic; plastid; -plasty; Polack; Poland; Pole; polka; protoplasm; veldt.

It is the hypothetical source of/evidence for its existence is provided by: Greek plassein "to mold," plasma "something molded or created;" Latin planus "flat, level, even, plain, clear;" Lithuanian plonas "thin;" Celtic *lanon "plain;" Old Church Slavonic polje "flat land, field," Russian polyi "open;" Old English feld, Middle Dutch veld "field."

mid-15c., Latinized spelling of Middle English spere (c. 1300) "cosmos; space, conceived as a hollow globe about the world," from Anglo-French espiere, Old French espere (13c., Modern French sphère), from Latin sphaera "globe, ball, celestial sphere" (Medieval Latin spera), from Greek sphaira "globe, ball, playing ball, terrestrial globe," a word of unknown origin.

From late 14c. in reference to any of the supposed concentric, transparent, hollow, crystalline globes of the cosmos believed to revolve around the earth and contain the planets and the fixed stars; the supposed harmonious sound they made rubbing against one another was the music of the spheres (late 14c.). Also from late 14c. as "a globe; object of spherical form, a ball," and the geometric sense "solid figure with all points equidistant from the center." Meaning "range of something, place or scene of activity" is first recorded c. 1600 (as in sphere of influence, 1885, originally in reference to Anglo-German colonial rivalry in Africa).