Lunary

A lunary (from Latin lunarium), also called a selenodromion or moonbook, is a book of prognostication based on the position of the moon at any given time.

[3] The lunary was "by far the most popular and widely circulated prognostic genre" during the Middle Ages.

In Middle English, lunarie referred to volvelles and not prognostic texts.

[6] Lunaries are similar to electionaries in that they were used for choosing (electing) astrological propitious dates for events.

[1] Lunaries were used for predicting and planning birth, business, death, illness, marriage, planting, phlebotomy and travel.

Latin lunary from the medical compendium St. Gallen, Stiftsbibliothek , Cod. Sang. 751, at p. 428