noun
source of a hot spring
Refers to the place where hot spring water emerges from the ground, often the origin point of an onsen. Also used in proper nouns.
この温泉の湯元は山の奥にある。
The source of this hot spring is deep in the mountains.
湯元の宿に泊まると、源泉かけ流しの湯を楽しめる。
If you stay at an inn at the hot spring source, you can enjoy the water flowing directly from the spring.
源泉 is a more general term for 'source' or 'spring', often used for hot springs but also for rivers or abstract origins. 湯元 specifically refers to the origin point of a hot spring.
Compound of 湯 (hot water) and 元 (origin, source). The spelling 湯本 uses 本 (origin) with the same meaning.