General Info: Part 1 - Onsen Glossary

I'm going to update this glossary constantly. If there are any onsen-related words you need explanation, please leave a comment. I'll follow up.

• ashiyu（足湯）: Foot bath. Usually free of charge except famous tourist spots like Arashiyama (Kyoto) and Yufuin (Oita). See the picture of this post.
• datsuijo（脱衣所）: Changing room.
• ganban-yoku（岩盤浴）: Stone sauna.
• furo（風呂）: Bath. Often means bath room as well. Ofuro is more polite expression.
• hinoki-buro（檜風呂）： Bath tub made of Japanese cypress woods.
• iwa-buro（岩風呂）：Bath tub made of rocks.
• kashikiri-buro（貸切風呂）: Private bath. You can share a bath with your family or friends. Same as kazoku-buro.
• kazoku-buro（家族風呂）: Private bath same as kashikiri-buro. Literally means family bath.
• konyoku（混浴）: Gender mixed bathing. Pronounce as kon-yoku.
• kousen（鉱泉）: Cold mineral springs.
• kyodo-yokujo（共同浴場）: Public bath. Admission fee is usually cheaper than sento.
• mizu-buro（水風呂）：Cold water bath.
• neyu（寝湯）: Lying Bath. Shallow bath with about 20 cm deep. Lying down for soaking.
• ofuro（お風呂）: Bath and bathroom. More polite than "furo".
• onna-yu（女湯）: Ladies' bath.
• onsen（温泉）: Hot springs. Also means hot spring bath, hot spring bath house, and whole hot spring gushing area depending on situation. Keep in mind an "ONSEN" named bath house sometimes supply heated tap or well water instead of hot springs (It's legal). See also Wikipedia.
• onsen tamago（温泉卵）：Eggs boiled with onsen. Softer than usual boiled egg.
• otoko-yu（男湯）: Men's bath.
• rei-kousen（冷鉱泉）: Cold mineral spring. Same as kousen.
• rotenburo（露天風呂）: Open-air bath.
• ryokan（旅館）: Japanese style inn. Generally serves dinner and breakfast for overnight staying guests. Many onsen ryokans accept day visit soaking.
• senmenki（洗面器）: Washing bowl.
• sento（銭湯）: Communal bath house for those who doesn't have a bath room at home. Some of them supply hot springs. Most of them are family run. All sentos are under authority of local governments and each prefecture set the addmission fee. Gender mixed bathing never allowed. See also Wikipedia.
• super sento（スーパー銭湯）: Value added sento with ganban-yoku, restaurant, barber, massage parlor, nail salon, and etc.
• uchiyu（内湯）: Usually means indoor bath, sometimes means bathroom inside ryokan.
• utaseyu（打たせ湯）：Pelting water. A steady stream of hot water cascading one's shoulders or back. Massaging effect expected.
• yukata（浴衣）: Cotton kimono. Almost all ryokans provide yukata for staying guest as bathrobe and pajama (Don't take away). See also Wikipedia.