scabbard, sheath
キースが背後に現れ、私の肩に鞘を掛けた。
Keith appeared behind me and slung a scabbard over my shoulder.
おめえ達もおとなしく鞘に入ってろよ
You guys stay put in your scabbards too.
— Sanjuro (1962)
でもなあの奥方が言った通り本当にいい刀は鞘に入ってる
But, you know, just like that lady said, a truly fine sword stays in its sheath.
でも本当にいい刀は鞘に入ってるもんですよ
But a truly good sword stays in its scabbard.