• 温泉おんせん — hot spring
• 泉水せんすい — fountain / spring water
• 名泉めいせん — famous spring
• 泉源せんげん — spring source
• 鉱泉こうせん — mineral spring
• 泉下せんか — the afterlife (poetic)

泉 is a pictograph of water emerging from rock — a natural spring. It appears in nature words (温泉) and figurative “sources.” Place names like 和泉 use the kun reading いずみ.