noun
Water with salinity between fresh water and seawater, typically found in estuaries.
この河口には汽水が広がっている。
Brackish water spreads across this river mouth.
汽水湖には独特の生態系がある。
Brackish-water lakes have unique ecosystems.
Compound of 汽 (vapor, steam) and 水 (water), referring to water that is neither fully fresh nor fully saline.