noun
tenth month of the lunar calendar
Obsolete term from the traditional Japanese lunar calendar. The month name uses the Earthly Branch 亥 (Boar), which was associated with the tenth month in the directional-month system. Not used in modern calendar contexts.
旧暦では亥月は冬の始まりにあたる。
In the old lunar calendar, the Boar Month marked the beginning of winter.
From Chinese 亥月 (hàiyuè), combining 亥 (the twelfth Earthly Branch, associated with the Boar and the direction north-northwest) and 月 (month). In the traditional East Asian directional-month system, the tenth lunar month corresponds to 亥.