Hierarchy classification:

1. top of the aat hierarchies
2. Associated Concepts Facet
3. Associated Concepts (hierarchy name)
4. multidisciplinary concepts
5. [dates and dating systems]
6. dating systems
7. [dating systems by general type]

Anotations

Scope note:

Dating system based on a year consisting of synodic months, which are complete cycles of phases of the Moon. In every solar year (or year of the seasons), there are about 12.37 synodic months. Therefore, if a lunar-year calendar is to be kept in step with the seasonal year, a periodic intercalation (addition) of days is necessary.