noun
Refers to the natural geothermal water itself, or the source. Often used in compound words like 温泉街 (hot spring town) or 温泉卵 (hot spring egg).
この地域にはたくさんの温泉が湧いている。
Many hot springs bubble up in this area.
温泉の成分が肌にいいらしい。
The minerals in the hot spring water are said to be good for the skin.
noun
onsen; hot spring resort; hot spring spa
Refers to a bathing facility or resort town built around a hot spring. Often implies a place with public baths, inns, and a relaxing atmosphere.
週末に温泉に行ってゆっくりしたい。
I want to go to a hot spring resort and relax this weekend.
あの温泉は露天風呂が有名だ。
That onsen is famous for its open-air bath.