An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

A year of 365 days that overlooks the fraction of less than 0.25 days corresponding to the whole length of the → tropical year. The vague year was used in the → calendars of ancient Egypt, Iran, Mayas, and some other civilizations. Typically the vague year was divided into 12 months of 30 days each plus 5 → epagomenal days.

From annus vagus "wandering year;" → vague→ year.