御湯[oyu] hot water
塩湯[shioyu] hot salt water (incl. bath)
温湯[ontou] comfortably hot bath
下湯[shimoyu] sitz bath
そと湯[sotoyu] open air bath (in an inn, onsen, etc.)

給湯[kyuutou] hot-water supply
給湯器[kyuutouki] hot-water heater
腰湯[koshiyu] sitting bath
重湯[omoyu] thin rice gruel
出で湯[ideyu] hot spring

亜熱帯[anettai] subtropics
悪熱[onetsu] fever following a chill
稲熱[imochi] rice blight
稲熱病[imochibyou] rice blight
炎熱[ennetsu] sweltering heat

温熱[onnetsu] hot fever
温熱性[onnetsusei] thermal
下熱[genetsu] lowering fever
加熱[kanetsu] heating
火熱[kanetsu] heat (from a flame)