case tablet

…When they were particularly needed, they were placed in a clay case. This was a kind of envelope, and the surface of the case was inscribed with the same records as the clay tablet inside, so it was called a "case tablet." When it became necessary to check the records, the envelope was broken open and the records inside were removed. …

*Some of the terminology explanations that mention "case tablet" are listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…とくに必要な場合は粘土のケースに入れられた。これは一種の封筒で，その表面にも中の粘土板と同じ記録が書かれたので，〈ケース･タブレットcase tablet〉と呼ばれる。確認の必要が生じたときには，封筒を割って中の記録を取り出した。…

※「case tablet」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報