volvelle

noun

Meaning

A rotating paper or parchment disk, often with pointers or cutouts, used in historical manuscripts and early printed books to represent astronomical cycles, calendars, or other cyclical data.

Examples

  • The medieval manuscript contained a complex volvelle showing the phases of the moon.
  • Early printed books sometimes included intricate volvelles that could be manipulated by the reader.

Synonyms: disk, wheel, dial, astrolabe component