from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. Plural form of volvelle.
Sorry, no etymologies found.
The spectacular full page images (...) are all volvelles (rotating paper wheel charts) and were used for various computations such as calculating the time and the lunar phases.
Bible and "Astronomicum Caesareum," a 17th century book of astronomical reckoning, complete with movable paper wheels (volvelles) used to calculate a planet's position.