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Definition of hot well in English:
hot well
noun
1A spring of naturally hot water; = "hot spring".
2Engineering. A reservoir or vessel into which heated water passes after use; specifically one that receives water from the condenser in a condensing steam engine or a steam turbine which is then used to supply the boiler.
Origin
Late Middle English; earliest use found in John Trevisa (c1342–?1402), translator. From hot + well.
