Chinese "Room" constellation (28 mansions)
Archaic astronomical term for the 房宿, the 4th of the 28 Chinese lunar mansions. Used in classical Japanese astronomy and astrology.
添い星は二十八宿の一つで、房宿にあたる。
Soiboshi is one of the 28 mansions, corresponding to the Room mansion.
In the past, the moon was sometimes called soiboshi.
Primary kanji spelling for the archaic astronomical term, combining 添い (accompanying) and 星 (star).
Variant spelling without okurigana, also used for the archaic astronomical term.
Alternate kanji using 房 (room/chamber), directly referencing the Chinese constellation name.
Alternate kanji using 宿 (lunar mansion), explicitly marking it as one of the 28 mansions.
The reading そいぼし likely derives from 添い (accompanying) + 星 (star), possibly referring to a star that accompanies another celestial body. The exact historical derivation is uncertain.