charnel house

a vault or other building in which the bones of the dead are stored

Japanese Meaning

死者の骨を収蔵するための建物（骨を納める建物） / 遺骨保管庫

They discovered a forgotten charnel house beneath the ruined chapel, its shelves lined with skulls and femurs.

彼らは廃れた礼拝堂の下に忘れられた納骨堂を発見し、棚には頭蓋骨や大腿骨が並んでいた。

Sense（1）

a vault or other building in which the bones of the dead are stored

charnel houses

（ plural ）