imperial ancestors; ancestors of the Imperial Family
Formal, historical term used in contexts related to the Japanese imperial lineage. Often appears in official or ceremonial language.
A ceremony was held to offer prayers to the spirits of the imperial ancestors.
Compound of 皇祖 (こうそ, 'imperial ancestor') and 皇宗 (こうそう, 'imperial lineage/ancestors'). The exact historical derivation is uncertain; the term is conventionally associated with the founding ancestors of the Japanese imperial line.