long, narrow house; eel bed house
Colloquial expression likening a very narrow, deep building to an eel's resting place. Often used for traditional Kyoto townhouses (町家) or similar narrow urban dwellings.
Kyoto townhouses are long, narrow houses called 'eel beds'.
この店はうなぎの寝床みたいに奥行きがある。
This shop is deep and narrow like an eel bed.