wash bucket; bathhouse bucket
A small bucket used in Japanese bathhouses (銭湯) for scooping water to rinse oneself before entering the communal bath.
銭湯で留桶にお湯を汲んで体を洗う。
At the bathhouse, I scoop hot water into the wash bucket and wash my body.
Compound of 留め (tome, 'stopping' or 'reserving') and 桶 (oke, 'bucket'). The exact derivation is uncertain; it may refer to a bucket kept at one's spot in the bathhouse.