autumnal imperial ancestor worship ceremony
A former imperial ceremony of ancestor worship held on the autumnal equinox (秋分の日). Now obsolete; the term is encountered only in historical contexts.
See also: 秋分の日
The Shūki Kōreisai was one of the imperial court rituals formerly held on the autumnal equinox.
Compound of 秋季 (autumn season), 皇 (imperial), 霊 (spirit), and 祭 (festival/ceremony). The term refers to a specific historical court ritual; the derivation is transparent from its components.