穴あな冠かんむり

noun

kanji 'hole' radical at top (穴)

Refers to the kanji radical 穴 (あな) when it appears at the top of a character, such as in 空, 究, or 窓. Used in discussing kanji structure.

• 「空そら」の上うえの部ぶ分ぶんは穴あな冠かんむりと呼よばれます。

  The top part of '空' is called 穴冠 (anakanmuri).