computus

Etymology

Borrowed from Latin computus. Doublet of conto and count.

computus means the calculation of the date of Easter in the Christian calendar. Lexicurio rates it Sui generis — a strength score of 92 out of 100.

Why this word is great

COMPUTUS — [Noun] The calculation, or a book of tables used for the calculation, of the date of Easter and other moveable feasts in the Christian calendar. From Latin computus (“computation, calculation”). Unlike a “calendar,” which broadly organizes the secular year, or an “almanac,” which forecasts earthly phenomena, a computus is a singular, sacred engine of chronology, bent on fixing a single, trembling point of light upon the dark wheel of time. It is the scratch of a quill tracing lunar cycles across vellum, the patient turning of a parchment wheel diagramming a cosmic dance, and the silent, annual triumph of a number found. In its dense tables, eternity finds a foothold in arithmetic.

noun

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.”
A book of tables for calculating dates of astronomical events and moveable feasts.“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 Ages, page 149, This computus also contains only one completed Plinian diagram, that for the planetary harmonic intervals.”