皇こう祖そ考こう

noun

deceased imperial grandfather

Formal, historical term referring specifically to the deceased grandfather of an emperor. Used in imperial household contexts.

• 皇こう祖そ考こうの御み霊たまに奉ほう告こくする儀ぎ式しきが行おこなわれた。

  A ceremony was held to report to the spirit of the deceased imperial grandfather.