Definition
An embolismic month is an extra lunar month inserted into a lunisolar calendar to keep its months aligned with the solar year and seasonal cycle. A year containing this addition is called an embolismic year. The term comes from a Greek word meaning “insertion.” Unlike a leap day in a solar calendar, the adjustment adds an entire lunar month.
Astrological Meaning
In traditional astrology, an embolismic month is primarily a calendrical feature rather than a planet, placement, aspect, or independent chart factor. It matters when interpreting texts and techniques based on historical lunisolar calendars, where months were regulated through observation or established intercalation cycles. Correctly identifying the inserted month can help establish dates, seasonal context, festivals, and the timing framework used by a particular culture. Its significance therefore depends on the calendar and astrological tradition being studied.
Why It Matters
Understanding embolismic months helps astrologers avoid transferring ancient dates directly into modern calendars without adjustment. A mistaken conversion can shift the recorded month or obscure its relationship to the season, even when the underlying planetary positions remain calculable. The concept is especially useful in historical research, traditional electional practice, and the study of lunar calendars. It does not, by itself, indicate a distinct personality trait or natal-chart outcome.
Related Encyclopedia Entries
- Traditional Astrology
- Astrological Terminology
- Natal Chart


