noun
low entrance door in Edo-period bathhouses
Historical term for a small, low door at the entrance of a public bathhouse (sento) during the Edo period, designed to minimize heat loss and keep the bathwater warm.
江戸時代の銭湯には、柘榴口と呼ばれる低い入り口があった。
In Edo-period public bathhouses, there was a low entrance called a 'zakuroguchi'.
柘榴口は
The zakuroguchi was made small to prevent steam from escaping.
A public bathhouse where a zakuroguchi would be found; the zakuroguchi is a specific architectural feature of such bathhouses.
The name likely derives from the resemblance of the small, low opening to a pomegranate (柘榴, zakuro) or its shape, but the exact origin is uncertain.