太たい陰いん太たい陽よう暦れき

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Meanings

1

noun

A calendar that uses both lunar months and solar years, such as the traditional Japanese calendar before the Meiji period.

plump, thick, big around

陰shade, yin, negative

陽sunshine, yang principle, positive

暦calendar, almanac

太たい陽よう暦れき
A solar calendar, based only on the sun's movement, unlike the lunisolar calendar which also tracks lunar phases.
太たい陰いん暦れき
A purely lunar calendar, ignoring the solar year, while the lunisolar calendar adjusts months to stay aligned with seasons.

From 太陰 (lunar) + 太陽 (solar) + 暦 (calendar). The term is a direct description of the calendar's dual basis.