noun
steam from hot water; hot spring steam
Refers specifically to the visible steam rising from hot water, especially in baths or hot springs.
露天風呂から湯煙が立ち上っている。
Steam is rising from the open-air bath.
蒸気 is general steam or vapor, often from boiling water or engines, while 湯煙 is specifically the visible steam from hot water in a bath or hot spring.
湯気 is steam from hot water or food, often used for everyday cooking or bathing; 湯煙 emphasizes the hazy, smoke-like appearance of steam rising from a hot spring or large bath.
Compound of 湯 (hot water) and 煙 (smoke), referring to the smoke-like steam rising from hot water.