noun
hot spring source; thermal spring source
Refers to the natural underground source or springhead that feeds a hot spring (温泉). Often used in geological, tourism, or onsen-development contexts.
この地域には多くの温泉源がある。
There are many hot spring sources in this area.
新しい温泉源を掘り当てた。
They struck a new hot spring source.
温泉 is the hot spring itself or the bathing facility; 温泉源 is the underground source that feeds it.
Compound of 温泉 (onsen, 'hot spring') and 源 (gen, 'source, origin').