computus

Noun

computus (countable and uncountable, plural computi)

1. The calculation of the date of Easter in the Christian calendar.
   • An elaborate bundle of techniques called computus therefore developed around Easter calculations. Computus formed the centerpiece of “scientific” education in the monasteries.2008, Ian F. McNeely, Lisa Wolverton, Reinventing Knowledge: From Alexandria to the Internet, page 68
   • Bede's work, which remained in active use for half a millennium, stood at the very center of the university curriculum, because the mastery of computus included many different essential subjects such as astronomy, mathematics, geography, theology, and law; its applications, too, included medicine...2011, Elisheva Carlbach, Palaces of Time, page 11
2. (historical) A book of tables for calculating dates of astronomical events and moveable feasts.
   • This computus also contains only one completed Plinian diagram, that for the planetary harmonic intervals.1987, Bruce Eastwood, 5: Plinian astronomical diagrams in the early Middle Ages, Edward Grant, John Emery Murdoch, Mathematics and Its Applications to Science and Natural Philosophy in the Middle...
   • Prognostics have thus been discovered in computi, in volumes on science or medicine, and in miscellanies which present a host of different text genres.2007, László Sándor Chardonnens, Anglo-Saxon Prognostics, 900-1100: Study and Texts, page 25