volvelle

American  

[vol-vel] / ˈvɒl vɛl /

noun

Astronomy.

1. a medieval instrument consisting of a series of concentric rotating disks, used to compute the phases of the moon and its position in relation to that of the sun.

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Etymology

Origin of volvelle

1400–50; late Middle English < Medieval Latin volvella, equivalent to Latin volv ( ere ) to turn + -ella -elle

Example Sentences

At the Morgan, the book is opened to a fanciful volvelle in which a green dragon with orange wings, representing the constellation Drago, serves as a pointer to indicate lunar and solar eclipses.

From New York Times

The first volvelle told what day Easter would fall in any year.

From New York Times

The volvelle becomes the early version of a diagram used for demonstrating a mathematical construction, but through the use of highly defined geometrical and topological structures to signify the mathematical framing of the heavenly entities in terms of their physical relationship to the human conscious perception. 

From Scientific American

This volvelle is taken from a French side detailing how calculations can be made with this volvelle involving the measurement ‘space-time’.

From Scientific American

Credit: assprouen.fr Everything about the volvelle, including the material of its construction, would place it squarely within the realm of the analog.

From Scientific American